1 | """A collection of string operations (most are no longer used).
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2 |
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3 | Warning: most of the code you see here isn't normally used nowadays.
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4 | Beginning with Python 1.6, many of these functions are implemented as
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5 | methods on the standard string object. They used to be implemented by
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6 | a built-in module called strop, but strop is now obsolete itself.
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7 |
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8 | Public module variables:
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9 |
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10 | whitespace -- a string containing all characters considered whitespace
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11 | lowercase -- a string containing all characters considered lowercase letters
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12 | uppercase -- a string containing all characters considered uppercase letters
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13 | letters -- a string containing all characters considered letters
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14 | digits -- a string containing all characters considered decimal digits
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15 | hexdigits -- a string containing all characters considered hexadecimal digits
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16 | octdigits -- a string containing all characters considered octal digits
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17 | punctuation -- a string containing all characters considered punctuation
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18 | printable -- a string containing all characters considered printable
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19 |
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20 | """
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21 |
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22 | # Some strings for ctype-style character classification
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23 | whitespace = ' \t\n\r\v\f'
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24 | lowercase = 'abcdefghijklmnopqrstuvwxyz'
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25 | uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
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26 | letters = lowercase + uppercase
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27 | ascii_lowercase = lowercase
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28 | ascii_uppercase = uppercase
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29 | ascii_letters = ascii_lowercase + ascii_uppercase
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30 | digits = '0123456789'
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31 | hexdigits = digits + 'abcdef' + 'ABCDEF'
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32 | octdigits = '01234567'
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33 | punctuation = """!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
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34 | printable = digits + letters + punctuation + whitespace
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35 |
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36 | # Case conversion helpers
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37 | # Use str to convert Unicode literal in case of -U
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38 | l = map(chr, xrange(256))
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39 | _idmap = str('').join(l)
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40 | del l
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41 |
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42 | # Functions which aren't available as string methods.
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43 |
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44 | # Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
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45 | def capwords(s, sep=None):
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46 | """capwords(s [,sep]) -> string
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47 |
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48 | Split the argument into words using split, capitalize each
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49 | word using capitalize, and join the capitalized words using
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50 | join. If the optional second argument sep is absent or None,
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51 | runs of whitespace characters are replaced by a single space
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52 | and leading and trailing whitespace are removed, otherwise
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53 | sep is used to split and join the words.
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54 |
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55 | """
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56 | return (sep or ' ').join(x.capitalize() for x in s.split(sep))
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57 |
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58 |
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59 | # Construct a translation string
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60 | _idmapL = None
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61 | def maketrans(fromstr, tostr):
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62 | """maketrans(frm, to) -> string
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63 |
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64 | Return a translation table (a string of 256 bytes long)
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65 | suitable for use in string.translate. The strings frm and to
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66 | must be of the same length.
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67 |
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68 | """
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69 | if len(fromstr) != len(tostr):
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70 | raise ValueError, "maketrans arguments must have same length"
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71 | global _idmapL
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72 | if not _idmapL:
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73 | _idmapL = list(_idmap)
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74 | L = _idmapL[:]
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75 | fromstr = map(ord, fromstr)
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76 | for i in range(len(fromstr)):
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77 | L[fromstr[i]] = tostr[i]
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78 | return ''.join(L)
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79 |
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80 |
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81 |
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82 | ####################################################################
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83 | import re as _re
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84 |
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85 | class _multimap:
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86 | """Helper class for combining multiple mappings.
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87 |
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88 | Used by .{safe_,}substitute() to combine the mapping and keyword
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89 | arguments.
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90 | """
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91 | def __init__(self, primary, secondary):
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92 | self._primary = primary
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93 | self._secondary = secondary
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94 |
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95 | def __getitem__(self, key):
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96 | try:
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97 | return self._primary[key]
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98 | except KeyError:
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99 | return self._secondary[key]
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100 |
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101 |
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102 | class _TemplateMetaclass(type):
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103 | pattern = r"""
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104 | %(delim)s(?:
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105 | (?P<escaped>%(delim)s) | # Escape sequence of two delimiters
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106 | (?P<named>%(id)s) | # delimiter and a Python identifier
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107 | {(?P<braced>%(id)s)} | # delimiter and a braced identifier
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108 | (?P<invalid>) # Other ill-formed delimiter exprs
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109 | )
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110 | """
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111 |
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112 | def __init__(cls, name, bases, dct):
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113 | super(_TemplateMetaclass, cls).__init__(name, bases, dct)
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114 | if 'pattern' in dct:
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115 | pattern = cls.pattern
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116 | else:
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117 | pattern = _TemplateMetaclass.pattern % {
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118 | 'delim' : _re.escape(cls.delimiter),
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119 | 'id' : cls.idpattern,
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120 | }
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121 | cls.pattern = _re.compile(pattern, _re.IGNORECASE | _re.VERBOSE)
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122 |
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123 |
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124 | class Template:
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125 | """A string class for supporting $-substitutions."""
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126 | __metaclass__ = _TemplateMetaclass
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127 |
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128 | delimiter = '$'
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129 | idpattern = r'[_a-z][_a-z0-9]*'
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130 |
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131 | def __init__(self, template):
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132 | self.template = template
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133 |
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134 | # Search for $$, $identifier, ${identifier}, and any bare $'s
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135 |
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136 | def _invalid(self, mo):
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137 | i = mo.start('invalid')
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138 | lines = self.template[:i].splitlines(True)
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139 | if not lines:
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140 | colno = 1
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141 | lineno = 1
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142 | else:
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143 | colno = i - len(''.join(lines[:-1]))
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144 | lineno = len(lines)
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145 | raise ValueError('Invalid placeholder in string: line %d, col %d' %
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146 | (lineno, colno))
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147 |
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148 | def substitute(self, *args, **kws):
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149 | if len(args) > 1:
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150 | raise TypeError('Too many positional arguments')
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151 | if not args:
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152 | mapping = kws
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153 | elif kws:
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154 | mapping = _multimap(kws, args[0])
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155 | else:
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156 | mapping = args[0]
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157 | # Helper function for .sub()
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158 | def convert(mo):
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159 | # Check the most common path first.
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160 | named = mo.group('named') or mo.group('braced')
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161 | if named is not None:
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162 | val = mapping[named]
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163 | # We use this idiom instead of str() because the latter will
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164 | # fail if val is a Unicode containing non-ASCII characters.
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165 | return '%s' % (val,)
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166 | if mo.group('escaped') is not None:
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167 | return self.delimiter
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168 | if mo.group('invalid') is not None:
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169 | self._invalid(mo)
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170 | raise ValueError('Unrecognized named group in pattern',
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171 | self.pattern)
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172 | return self.pattern.sub(convert, self.template)
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173 |
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174 | def safe_substitute(self, *args, **kws):
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175 | if len(args) > 1:
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176 | raise TypeError('Too many positional arguments')
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177 | if not args:
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178 | mapping = kws
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179 | elif kws:
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180 | mapping = _multimap(kws, args[0])
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181 | else:
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182 | mapping = args[0]
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183 | # Helper function for .sub()
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184 | def convert(mo):
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185 | named = mo.group('named')
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186 | if named is not None:
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187 | try:
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188 | # We use this idiom instead of str() because the latter
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189 | # will fail if val is a Unicode containing non-ASCII
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190 | return '%s' % (mapping[named],)
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191 | except KeyError:
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192 | return self.delimiter + named
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193 | braced = mo.group('braced')
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194 | if braced is not None:
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195 | try:
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196 | return '%s' % (mapping[braced],)
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197 | except KeyError:
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198 | return self.delimiter + '{' + braced + '}'
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199 | if mo.group('escaped') is not None:
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200 | return self.delimiter
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201 | if mo.group('invalid') is not None:
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202 | return self.delimiter
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203 | raise ValueError('Unrecognized named group in pattern',
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204 | self.pattern)
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205 | return self.pattern.sub(convert, self.template)
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206 |
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207 |
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208 |
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209 | ####################################################################
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210 | # NOTE: Everything below here is deprecated. Use string methods instead.
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211 | # This stuff will go away in Python 3.0.
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212 |
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213 | # Backward compatible names for exceptions
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214 | index_error = ValueError
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215 | atoi_error = ValueError
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216 | atof_error = ValueError
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217 | atol_error = ValueError
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218 |
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219 | # convert UPPER CASE letters to lower case
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220 | def lower(s):
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221 | """lower(s) -> string
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222 |
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223 | Return a copy of the string s converted to lowercase.
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224 |
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225 | """
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226 | return s.lower()
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227 |
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228 | # Convert lower case letters to UPPER CASE
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229 | def upper(s):
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230 | """upper(s) -> string
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231 |
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232 | Return a copy of the string s converted to uppercase.
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233 |
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234 | """
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235 | return s.upper()
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236 |
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237 | # Swap lower case letters and UPPER CASE
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238 | def swapcase(s):
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239 | """swapcase(s) -> string
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240 |
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241 | Return a copy of the string s with upper case characters
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242 | converted to lowercase and vice versa.
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243 |
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244 | """
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245 | return s.swapcase()
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246 |
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247 | # Strip leading and trailing tabs and spaces
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248 | def strip(s, chars=None):
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249 | """strip(s [,chars]) -> string
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250 |
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251 | Return a copy of the string s with leading and trailing
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252 | whitespace removed.
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253 | If chars is given and not None, remove characters in chars instead.
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254 | If chars is unicode, S will be converted to unicode before stripping.
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255 |
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256 | """
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257 | return s.strip(chars)
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258 |
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259 | # Strip leading tabs and spaces
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260 | def lstrip(s, chars=None):
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261 | """lstrip(s [,chars]) -> string
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262 |
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263 | Return a copy of the string s with leading whitespace removed.
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264 | If chars is given and not None, remove characters in chars instead.
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265 |
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266 | """
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267 | return s.lstrip(chars)
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268 |
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269 | # Strip trailing tabs and spaces
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270 | def rstrip(s, chars=None):
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271 | """rstrip(s [,chars]) -> string
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272 |
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273 | Return a copy of the string s with trailing whitespace removed.
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274 | If chars is given and not None, remove characters in chars instead.
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275 |
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276 | """
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277 | return s.rstrip(chars)
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278 |
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279 |
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280 | # Split a string into a list of space/tab-separated words
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281 | def split(s, sep=None, maxsplit=-1):
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282 | """split(s [,sep [,maxsplit]]) -> list of strings
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283 |
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284 | Return a list of the words in the string s, using sep as the
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285 | delimiter string. If maxsplit is given, splits at no more than
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286 | maxsplit places (resulting in at most maxsplit+1 words). If sep
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287 | is not specified or is None, any whitespace string is a separator.
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288 |
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289 | (split and splitfields are synonymous)
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290 |
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291 | """
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292 | return s.split(sep, maxsplit)
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293 | splitfields = split
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294 |
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295 | # Split a string into a list of space/tab-separated words
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296 | def rsplit(s, sep=None, maxsplit=-1):
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297 | """rsplit(s [,sep [,maxsplit]]) -> list of strings
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298 |
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299 | Return a list of the words in the string s, using sep as the
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300 | delimiter string, starting at the end of the string and working
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301 | to the front. If maxsplit is given, at most maxsplit splits are
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302 | done. If sep is not specified or is None, any whitespace string
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303 | is a separator.
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304 | """
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305 | return s.rsplit(sep, maxsplit)
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306 |
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307 | # Join fields with optional separator
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308 | def join(words, sep = ' '):
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309 | """join(list [,sep]) -> string
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310 |
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311 | Return a string composed of the words in list, with
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312 | intervening occurrences of sep. The default separator is a
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313 | single space.
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314 |
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315 | (joinfields and join are synonymous)
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316 |
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317 | """
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318 | return sep.join(words)
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319 | joinfields = join
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320 |
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321 | # Find substring, raise exception if not found
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322 | def index(s, *args):
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323 | """index(s, sub [,start [,end]]) -> int
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324 |
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325 | Like find but raises ValueError when the substring is not found.
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326 |
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327 | """
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328 | return s.index(*args)
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329 |
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330 | # Find last substring, raise exception if not found
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331 | def rindex(s, *args):
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332 | """rindex(s, sub [,start [,end]]) -> int
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333 |
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334 | Like rfind but raises ValueError when the substring is not found.
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335 |
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336 | """
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337 | return s.rindex(*args)
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338 |
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339 | # Count non-overlapping occurrences of substring
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340 | def count(s, *args):
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341 | """count(s, sub[, start[,end]]) -> int
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342 |
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343 | Return the number of occurrences of substring sub in string
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344 | s[start:end]. Optional arguments start and end are
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345 | interpreted as in slice notation.
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346 |
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347 | """
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348 | return s.count(*args)
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349 |
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350 | # Find substring, return -1 if not found
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351 | def find(s, *args):
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352 | """find(s, sub [,start [,end]]) -> in
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353 |
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354 | Return the lowest index in s where substring sub is found,
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355 | such that sub is contained within s[start,end]. Optional
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356 | arguments start and end are interpreted as in slice notation.
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357 |
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358 | Return -1 on failure.
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359 |
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360 | """
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361 | return s.find(*args)
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362 |
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363 | # Find last substring, return -1 if not found
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364 | def rfind(s, *args):
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365 | """rfind(s, sub [,start [,end]]) -> int
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366 |
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367 | Return the highest index in s where substring sub is found,
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368 | such that sub is contained within s[start,end]. Optional
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369 | arguments start and end are interpreted as in slice notation.
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370 |
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371 | Return -1 on failure.
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372 |
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373 | """
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374 | return s.rfind(*args)
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375 |
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376 | # for a bit of speed
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377 | _float = float
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378 | _int = int
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379 | _long = long
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380 |
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381 | # Convert string to float
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382 | def atof(s):
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383 | """atof(s) -> float
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384 |
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385 | Return the floating point number represented by the string s.
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386 |
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387 | """
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388 | return _float(s)
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389 |
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390 |
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391 | # Convert string to integer
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392 | def atoi(s , base=10):
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393 | """atoi(s [,base]) -> int
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394 |
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395 | Return the integer represented by the string s in the given
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396 | base, which defaults to 10. The string s must consist of one
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397 | or more digits, possibly preceded by a sign. If base is 0, it
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398 | is chosen from the leading characters of s, 0 for octal, 0x or
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399 | 0X for hexadecimal. If base is 16, a preceding 0x or 0X is
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400 | accepted.
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401 |
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402 | """
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403 | return _int(s, base)
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404 |
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405 |
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406 | # Convert string to long integer
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407 | def atol(s, base=10):
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408 | """atol(s [,base]) -> long
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409 |
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410 | Return the long integer represented by the string s in the
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411 | given base, which defaults to 10. The string s must consist
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412 | of one or more digits, possibly preceded by a sign. If base
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413 | is 0, it is chosen from the leading characters of s, 0 for
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414 | octal, 0x or 0X for hexadecimal. If base is 16, a preceding
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415 | 0x or 0X is accepted. A trailing L or l is not accepted,
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416 | unless base is 0.
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417 |
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418 | """
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419 | return _long(s, base)
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420 |
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421 |
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422 | # Left-justify a string
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423 | def ljust(s, width, *args):
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424 | """ljust(s, width[, fillchar]) -> string
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425 |
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426 | Return a left-justified version of s, in a field of the
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427 | specified width, padded with spaces as needed. The string is
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428 | never truncated. If specified the fillchar is used instead of spaces.
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429 |
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430 | """
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431 | return s.ljust(width, *args)
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432 |
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433 | # Right-justify a string
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434 | def rjust(s, width, *args):
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435 | """rjust(s, width[, fillchar]) -> string
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436 |
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437 | Return a right-justified version of s, in a field of the
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438 | specified width, padded with spaces as needed. The string is
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439 | never truncated. If specified the fillchar is used instead of spaces.
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440 |
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441 | """
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442 | return s.rjust(width, *args)
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443 |
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444 | # Center a string
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445 | def center(s, width, *args):
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446 | """center(s, width[, fillchar]) -> string
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447 |
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448 | Return a center version of s, in a field of the specified
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449 | width. padded with spaces as needed. The string is never
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450 | truncated. If specified the fillchar is used instead of spaces.
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451 |
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452 | """
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453 | return s.center(width, *args)
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454 |
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455 | # Zero-fill a number, e.g., (12, 3) --> '012' and (-3, 3) --> '-03'
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456 | # Decadent feature: the argument may be a string or a number
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457 | # (Use of this is deprecated; it should be a string as with ljust c.s.)
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458 | def zfill(x, width):
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459 | """zfill(x, width) -> string
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460 |
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461 | Pad a numeric string x with zeros on the left, to fill a field
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462 | of the specified width. The string x is never truncated.
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463 |
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464 | """
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465 | if not isinstance(x, basestring):
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466 | x = repr(x)
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467 | return x.zfill(width)
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468 |
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469 | # Expand tabs in a string.
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470 | # Doesn't take non-printing chars into account, but does understand \n.
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471 | def expandtabs(s, tabsize=8):
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472 | """expandtabs(s [,tabsize]) -> string
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473 |
|
---|
474 | Return a copy of the string s with all tab characters replaced
|
---|
475 | by the appropriate number of spaces, depending on the current
|
---|
476 | column, and the tabsize (default 8).
|
---|
477 |
|
---|
478 | """
|
---|
479 | return s.expandtabs(tabsize)
|
---|
480 |
|
---|
481 | # Character translation through look-up table.
|
---|
482 | def translate(s, table, deletions=""):
|
---|
483 | """translate(s,table [,deletions]) -> string
|
---|
484 |
|
---|
485 | Return a copy of the string s, where all characters occurring
|
---|
486 | in the optional argument deletions are removed, and the
|
---|
487 | remaining characters have been mapped through the given
|
---|
488 | translation table, which must be a string of length 256. The
|
---|
489 | deletions argument is not allowed for Unicode strings.
|
---|
490 |
|
---|
491 | """
|
---|
492 | if deletions or table is None:
|
---|
493 | return s.translate(table, deletions)
|
---|
494 | else:
|
---|
495 | # Add s[:0] so that if s is Unicode and table is an 8-bit string,
|
---|
496 | # table is converted to Unicode. This means that table *cannot*
|
---|
497 | # be a dictionary -- for that feature, use u.translate() directly.
|
---|
498 | return s.translate(table + s[:0])
|
---|
499 |
|
---|
500 | # Capitalize a string, e.g. "aBc dEf" -> "Abc def".
|
---|
501 | def capitalize(s):
|
---|
502 | """capitalize(s) -> string
|
---|
503 |
|
---|
504 | Return a copy of the string s with only its first character
|
---|
505 | capitalized.
|
---|
506 |
|
---|
507 | """
|
---|
508 | return s.capitalize()
|
---|
509 |
|
---|
510 | # Substring replacement (global)
|
---|
511 | def replace(s, old, new, maxreplace=-1):
|
---|
512 | """replace (str, old, new[, maxreplace]) -> string
|
---|
513 |
|
---|
514 | Return a copy of string str with all occurrences of substring
|
---|
515 | old replaced by new. If the optional argument maxreplace is
|
---|
516 | given, only the first maxreplace occurrences are replaced.
|
---|
517 |
|
---|
518 | """
|
---|
519 | return s.replace(old, new, maxreplace)
|
---|
520 |
|
---|
521 |
|
---|
522 | # Try importing optional built-in module "strop" -- if it exists,
|
---|
523 | # it redefines some string operations that are 100-1000 times faster.
|
---|
524 | # It also defines values for whitespace, lowercase and uppercase
|
---|
525 | # that match <ctype.h>'s definitions.
|
---|
526 |
|
---|
527 | try:
|
---|
528 | from strop import maketrans, lowercase, uppercase, whitespace
|
---|
529 | letters = lowercase + uppercase
|
---|
530 | except ImportError:
|
---|
531 | pass # Use the original versions
|
---|
532 |
|
---|
533 | ########################################################################
|
---|
534 | # the Formatter class
|
---|
535 | # see PEP 3101 for details and purpose of this class
|
---|
536 |
|
---|
537 | # The hard parts are reused from the C implementation. They're exposed as "_"
|
---|
538 | # prefixed methods of str and unicode.
|
---|
539 |
|
---|
540 | # The overall parser is implemented in str._formatter_parser.
|
---|
541 | # The field name parser is implemented in str._formatter_field_name_split
|
---|
542 |
|
---|
543 | class Formatter(object):
|
---|
544 | def format(self, format_string, *args, **kwargs):
|
---|
545 | return self.vformat(format_string, args, kwargs)
|
---|
546 |
|
---|
547 | def vformat(self, format_string, args, kwargs):
|
---|
548 | used_args = set()
|
---|
549 | result = self._vformat(format_string, args, kwargs, used_args, 2)
|
---|
550 | self.check_unused_args(used_args, args, kwargs)
|
---|
551 | return result
|
---|
552 |
|
---|
553 | def _vformat(self, format_string, args, kwargs, used_args, recursion_depth):
|
---|
554 | if recursion_depth < 0:
|
---|
555 | raise ValueError('Max string recursion exceeded')
|
---|
556 | result = []
|
---|
557 | for literal_text, field_name, format_spec, conversion in \
|
---|
558 | self.parse(format_string):
|
---|
559 |
|
---|
560 | # output the literal text
|
---|
561 | if literal_text:
|
---|
562 | result.append(literal_text)
|
---|
563 |
|
---|
564 | # if there's a field, output it
|
---|
565 | if field_name is not None:
|
---|
566 | # this is some markup, find the object and do
|
---|
567 | # the formatting
|
---|
568 |
|
---|
569 | # given the field_name, find the object it references
|
---|
570 | # and the argument it came from
|
---|
571 | obj, arg_used = self.get_field(field_name, args, kwargs)
|
---|
572 | used_args.add(arg_used)
|
---|
573 |
|
---|
574 | # do any conversion on the resulting object
|
---|
575 | obj = self.convert_field(obj, conversion)
|
---|
576 |
|
---|
577 | # expand the format spec, if needed
|
---|
578 | format_spec = self._vformat(format_spec, args, kwargs,
|
---|
579 | used_args, recursion_depth-1)
|
---|
580 |
|
---|
581 | # format the object and append to the result
|
---|
582 | result.append(self.format_field(obj, format_spec))
|
---|
583 |
|
---|
584 | return ''.join(result)
|
---|
585 |
|
---|
586 |
|
---|
587 | def get_value(self, key, args, kwargs):
|
---|
588 | if isinstance(key, (int, long)):
|
---|
589 | return args[key]
|
---|
590 | else:
|
---|
591 | return kwargs[key]
|
---|
592 |
|
---|
593 |
|
---|
594 | def check_unused_args(self, used_args, args, kwargs):
|
---|
595 | pass
|
---|
596 |
|
---|
597 |
|
---|
598 | def format_field(self, value, format_spec):
|
---|
599 | return format(value, format_spec)
|
---|
600 |
|
---|
601 |
|
---|
602 | def convert_field(self, value, conversion):
|
---|
603 | # do any conversion on the resulting object
|
---|
604 | if conversion is None:
|
---|
605 | return value
|
---|
606 | elif conversion == 's':
|
---|
607 | return str(value)
|
---|
608 | elif conversion == 'r':
|
---|
609 | return repr(value)
|
---|
610 | raise ValueError("Unknown conversion specifier {0!s}".format(conversion))
|
---|
611 |
|
---|
612 |
|
---|
613 | # returns an iterable that contains tuples of the form:
|
---|
614 | # (literal_text, field_name, format_spec, conversion)
|
---|
615 | # literal_text can be zero length
|
---|
616 | # field_name can be None, in which case there's no
|
---|
617 | # object to format and output
|
---|
618 | # if field_name is not None, it is looked up, formatted
|
---|
619 | # with format_spec and conversion and then used
|
---|
620 | def parse(self, format_string):
|
---|
621 | return format_string._formatter_parser()
|
---|
622 |
|
---|
623 |
|
---|
624 | # given a field_name, find the object it references.
|
---|
625 | # field_name: the field being looked up, e.g. "0.name"
|
---|
626 | # or "lookup[3]"
|
---|
627 | # used_args: a set of which args have been used
|
---|
628 | # args, kwargs: as passed in to vformat
|
---|
629 | def get_field(self, field_name, args, kwargs):
|
---|
630 | first, rest = field_name._formatter_field_name_split()
|
---|
631 |
|
---|
632 | obj = self.get_value(first, args, kwargs)
|
---|
633 |
|
---|
634 | # loop through the rest of the field_name, doing
|
---|
635 | # getattr or getitem as needed
|
---|
636 | for is_attr, i in rest:
|
---|
637 | if is_attr:
|
---|
638 | obj = getattr(obj, i)
|
---|
639 | else:
|
---|
640 | obj = obj[i]
|
---|
641 |
|
---|
642 | return obj, first
|
---|