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530 lines
16 KiB
Python
530 lines
16 KiB
Python
"""A collection of string operations (most are no longer used).
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Warning: most of the code you see here isn't normally used nowadays.
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Beginning with Python 1.6, many of these functions are implemented as
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methods on the standard string object. They used to be implemented by
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a built-in module called strop, but strop is now obsolete itself.
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Public module variables:
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whitespace -- a string containing all characters considered whitespace
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lowercase -- a string containing all characters considered lowercase letters
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uppercase -- a string containing all characters considered uppercase letters
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letters -- a string containing all characters considered letters
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digits -- a string containing all characters considered decimal digits
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hexdigits -- a string containing all characters considered hexadecimal digits
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octdigits -- a string containing all characters considered octal digits
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punctuation -- a string containing all characters considered punctuation
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printable -- a string containing all characters considered printable
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"""
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# Some strings for ctype-style character classification
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whitespace = ' \t\n\r\v\f'
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lowercase = 'abcdefghijklmnopqrstuvwxyz'
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uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
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letters = lowercase + uppercase
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ascii_lowercase = lowercase
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ascii_uppercase = uppercase
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ascii_letters = ascii_lowercase + ascii_uppercase
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digits = '0123456789'
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hexdigits = digits + 'abcdef' + 'ABCDEF'
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octdigits = '01234567'
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punctuation = """!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
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printable = digits + letters + punctuation + whitespace
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# Case conversion helpers
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# Use str to convert Unicode literal in case of -U
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l = map(chr, xrange(256))
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_idmap = str('').join(l)
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del l
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# Functions which aren't available as string methods.
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# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
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def capwords(s, sep=None):
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"""capwords(s, [sep]) -> string
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Split the argument into words using split, capitalize each
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word using capitalize, and join the capitalized words using
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join. Note that this replaces runs of whitespace characters by
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a single space.
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"""
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return (sep or ' ').join([x.capitalize() for x in s.split(sep)])
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# Construct a translation string
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_idmapL = None
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def maketrans(fromstr, tostr):
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"""maketrans(frm, to) -> string
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Return a translation table (a string of 256 bytes long)
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suitable for use in string.translate. The strings frm and to
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must be of the same length.
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"""
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if len(fromstr) != len(tostr):
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raise ValueError, "maketrans arguments must have same length"
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global _idmapL
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if not _idmapL:
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_idmapL = map(None, _idmap)
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L = _idmapL[:]
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fromstr = map(ord, fromstr)
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for i in range(len(fromstr)):
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L[fromstr[i]] = tostr[i]
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return ''.join(L)
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####################################################################
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import re as _re
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class _multimap:
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"""Helper class for combining multiple mappings.
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Used by .{safe_,}substitute() to combine the mapping and keyword
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arguments.
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"""
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def __init__(self, primary, secondary):
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self._primary = primary
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self._secondary = secondary
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def __getitem__(self, key):
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try:
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return self._primary[key]
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except KeyError:
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return self._secondary[key]
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class _TemplateMetaclass(type):
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pattern = r"""
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%(delim)s(?:
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(?P<escaped>%(delim)s) | # Escape sequence of two delimiters
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(?P<named>%(id)s) | # delimiter and a Python identifier
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{(?P<braced>%(id)s)} | # delimiter and a braced identifier
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(?P<invalid>) # Other ill-formed delimiter exprs
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)
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"""
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def __init__(cls, name, bases, dct):
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super(_TemplateMetaclass, cls).__init__(name, bases, dct)
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if 'pattern' in dct:
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pattern = cls.pattern
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else:
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pattern = _TemplateMetaclass.pattern % {
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'delim' : _re.escape(cls.delimiter),
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'id' : cls.idpattern,
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}
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cls.pattern = _re.compile(pattern, _re.IGNORECASE | _re.VERBOSE)
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class Template:
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"""A string class for supporting $-substitutions."""
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__metaclass__ = _TemplateMetaclass
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delimiter = '$'
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idpattern = r'[_a-z][_a-z0-9]*'
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def __init__(self, template):
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self.template = template
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# Search for $$, $identifier, ${identifier}, and any bare $'s
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def _invalid(self, mo):
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i = mo.start('invalid')
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lines = self.template[:i].splitlines(True)
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if not lines:
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colno = 1
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lineno = 1
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else:
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colno = i - len(''.join(lines[:-1]))
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lineno = len(lines)
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raise ValueError('Invalid placeholder in string: line %d, col %d' %
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(lineno, colno))
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def substitute(self, *args, **kws):
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if len(args) > 1:
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raise TypeError('Too many positional arguments')
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if not args:
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mapping = kws
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elif kws:
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mapping = _multimap(kws, args[0])
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else:
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mapping = args[0]
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# Helper function for .sub()
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def convert(mo):
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# Check the most common path first.
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named = mo.group('named') or mo.group('braced')
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if named is not None:
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val = mapping[named]
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# We use this idiom instead of str() because the latter will
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# fail if val is a Unicode containing non-ASCII characters.
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return '%s' % (val,)
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if mo.group('escaped') is not None:
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return self.delimiter
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if mo.group('invalid') is not None:
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self._invalid(mo)
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raise ValueError('Unrecognized named group in pattern',
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self.pattern)
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return self.pattern.sub(convert, self.template)
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def safe_substitute(self, *args, **kws):
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if len(args) > 1:
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raise TypeError('Too many positional arguments')
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if not args:
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mapping = kws
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elif kws:
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mapping = _multimap(kws, args[0])
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else:
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mapping = args[0]
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# Helper function for .sub()
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def convert(mo):
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named = mo.group('named')
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if named is not None:
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try:
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# We use this idiom instead of str() because the latter
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# will fail if val is a Unicode containing non-ASCII
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return '%s' % (mapping[named],)
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except KeyError:
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return self.delimiter + named
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braced = mo.group('braced')
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if braced is not None:
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try:
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return '%s' % (mapping[braced],)
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except KeyError:
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return self.delimiter + '{' + braced + '}'
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if mo.group('escaped') is not None:
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return self.delimiter
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if mo.group('invalid') is not None:
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return self.delimiter
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raise ValueError('Unrecognized named group in pattern',
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self.pattern)
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return self.pattern.sub(convert, self.template)
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####################################################################
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# NOTE: Everything below here is deprecated. Use string methods instead.
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# This stuff will go away in Python 3.0.
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# Backward compatible names for exceptions
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index_error = ValueError
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atoi_error = ValueError
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atof_error = ValueError
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atol_error = ValueError
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# convert UPPER CASE letters to lower case
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def lower(s):
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"""lower(s) -> string
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Return a copy of the string s converted to lowercase.
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"""
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return s.lower()
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# Convert lower case letters to UPPER CASE
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def upper(s):
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"""upper(s) -> string
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Return a copy of the string s converted to uppercase.
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"""
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return s.upper()
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# Swap lower case letters and UPPER CASE
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def swapcase(s):
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"""swapcase(s) -> string
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Return a copy of the string s with upper case characters
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converted to lowercase and vice versa.
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"""
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return s.swapcase()
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# Strip leading and trailing tabs and spaces
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def strip(s, chars=None):
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"""strip(s [,chars]) -> string
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Return a copy of the string s with leading and trailing
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whitespace removed.
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If chars is given and not None, remove characters in chars instead.
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If chars is unicode, S will be converted to unicode before stripping.
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"""
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return s.strip(chars)
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# Strip leading tabs and spaces
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def lstrip(s, chars=None):
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"""lstrip(s [,chars]) -> string
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Return a copy of the string s with leading whitespace removed.
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If chars is given and not None, remove characters in chars instead.
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"""
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return s.lstrip(chars)
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# Strip trailing tabs and spaces
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def rstrip(s, chars=None):
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"""rstrip(s [,chars]) -> string
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Return a copy of the string s with trailing whitespace removed.
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If chars is given and not None, remove characters in chars instead.
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"""
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return s.rstrip(chars)
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# Split a string into a list of space/tab-separated words
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def split(s, sep=None, maxsplit=-1):
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"""split(s [,sep [,maxsplit]]) -> list of strings
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Return a list of the words in the string s, using sep as the
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delimiter string. If maxsplit is given, splits at no more than
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maxsplit places (resulting in at most maxsplit+1 words). If sep
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is not specified or is None, any whitespace string is a separator.
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(split and splitfields are synonymous)
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"""
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return s.split(sep, maxsplit)
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splitfields = split
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# Split a string into a list of space/tab-separated words
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def rsplit(s, sep=None, maxsplit=-1):
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"""rsplit(s [,sep [,maxsplit]]) -> list of strings
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Return a list of the words in the string s, using sep as the
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delimiter string, starting at the end of the string and working
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to the front. If maxsplit is given, at most maxsplit splits are
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done. If sep is not specified or is None, any whitespace string
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is a separator.
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"""
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return s.rsplit(sep, maxsplit)
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# Join fields with optional separator
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def join(words, sep = ' '):
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"""join(list [,sep]) -> string
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Return a string composed of the words in list, with
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intervening occurrences of sep. The default separator is a
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single space.
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(joinfields and join are synonymous)
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"""
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return sep.join(words)
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joinfields = join
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# Find substring, raise exception if not found
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def index(s, *args):
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"""index(s, sub [,start [,end]]) -> int
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Like find but raises ValueError when the substring is not found.
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"""
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return s.index(*args)
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# Find last substring, raise exception if not found
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def rindex(s, *args):
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"""rindex(s, sub [,start [,end]]) -> int
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Like rfind but raises ValueError when the substring is not found.
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"""
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return s.rindex(*args)
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# Count non-overlapping occurrences of substring
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def count(s, *args):
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"""count(s, sub[, start[,end]]) -> int
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Return the number of occurrences of substring sub in string
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s[start:end]. Optional arguments start and end are
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interpreted as in slice notation.
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"""
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return s.count(*args)
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# Find substring, return -1 if not found
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def find(s, *args):
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"""find(s, sub [,start [,end]]) -> in
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Return the lowest index in s where substring sub is found,
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such that sub is contained within s[start,end]. Optional
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arguments start and end are interpreted as in slice notation.
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Return -1 on failure.
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"""
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return s.find(*args)
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# Find last substring, return -1 if not found
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def rfind(s, *args):
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"""rfind(s, sub [,start [,end]]) -> int
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Return the highest index in s where substring sub is found,
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such that sub is contained within s[start,end]. Optional
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arguments start and end are interpreted as in slice notation.
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Return -1 on failure.
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"""
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return s.rfind(*args)
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# for a bit of speed
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_float = float
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_int = int
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_long = int
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# Convert string to float
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def atof(s):
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"""atof(s) -> float
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Return the floating point number represented by the string s.
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"""
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return _float(s)
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# Convert string to integer
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def atoi(s , base=10):
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"""atoi(s [,base]) -> int
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Return the integer represented by the string s in the given
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base, which defaults to 10. The string s must consist of one
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or more digits, possibly preceded by a sign. If base is 0, it
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is chosen from the leading characters of s, 0 for octal, 0x or
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0X for hexadecimal. If base is 16, a preceding 0x or 0X is
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accepted.
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"""
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return _int(s, base)
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# Convert string to long integer
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def atol(s, base=10):
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"""atol(s [,base]) -> long
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Return the long integer represented by the string s in the
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given base, which defaults to 10. The string s must consist
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of one or more digits, possibly preceded by a sign. If base
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is 0, it is chosen from the leading characters of s, 0 for
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octal, 0x or 0X for hexadecimal. If base is 16, a preceding
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0x or 0X is accepted. A trailing L or l is not accepted,
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unless base is 0.
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"""
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return _long(s, base)
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# Left-justify a string
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def ljust(s, width, *args):
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"""ljust(s, width[, fillchar]) -> string
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Return a left-justified version of s, in a field of the
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specified width, padded with spaces as needed. The string is
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never truncated. If specified the fillchar is used instead of spaces.
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"""
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return s.ljust(width, *args)
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# Right-justify a string
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def rjust(s, width, *args):
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"""rjust(s, width[, fillchar]) -> string
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Return a right-justified version of s, in a field of the
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specified width, padded with spaces as needed. The string is
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never truncated. If specified the fillchar is used instead of spaces.
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"""
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return s.rjust(width, *args)
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# Center a string
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def center(s, width, *args):
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"""center(s, width[, fillchar]) -> string
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Return a center version of s, in a field of the specified
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width. padded with spaces as needed. The string is never
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truncated. If specified the fillchar is used instead of spaces.
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"""
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return s.center(width, *args)
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# Zero-fill a number, e.g., (12, 3) --> '012' and (-3, 3) --> '-03'
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# Decadent feature: the argument may be a string or a number
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# (Use of this is deprecated; it should be a string as with ljust c.s.)
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def zfill(x, width):
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"""zfill(x, width) -> string
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Pad a numeric string x with zeros on the left, to fill a field
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of the specified width. The string x is never truncated.
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"""
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if not isinstance(x, basestring):
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x = repr(x)
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return x.zfill(width)
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# Expand tabs in a string.
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# Doesn't take non-printing chars into account, but does understand \n.
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def expandtabs(s, tabsize=8):
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"""expandtabs(s [,tabsize]) -> string
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Return a copy of the string s with all tab characters replaced
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by the appropriate number of spaces, depending on the current
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column, and the tabsize (default 8).
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"""
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return s.expandtabs(tabsize)
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# Character translation through look-up table.
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def translate(s, table, deletions=""):
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"""translate(s,table [,deletions]) -> string
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Return a copy of the string s, where all characters occurring
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in the optional argument deletions are removed, and the
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remaining characters have been mapped through the given
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translation table, which must be a string of length 256. The
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deletions argument is not allowed for Unicode strings.
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"""
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if deletions:
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return s.translate(table, deletions)
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else:
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# Add s[:0] so that if s is Unicode and table is an 8-bit string,
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# table is converted to Unicode. This means that table *cannot*
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# be a dictionary -- for that feature, use u.translate() directly.
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return s.translate(table + s[:0])
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# Capitalize a string, e.g. "aBc dEf" -> "Abc def".
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def capitalize(s):
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"""capitalize(s) -> string
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Return a copy of the string s with only its first character
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capitalized.
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"""
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return s.capitalize()
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# Substring replacement (global)
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def replace(s, old, new, maxsplit=-1):
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"""replace (str, old, new[, maxsplit]) -> string
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Return a copy of string str with all occurrences of substring
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old replaced by new. If the optional argument maxsplit is
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given, only the first maxsplit occurrences are replaced.
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"""
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return s.replace(old, new, maxsplit)
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# Try importing optional built-in module "strop" -- if it exists,
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# it redefines some string operations that are 100-1000 times faster.
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# It also defines values for whitespace, lowercase and uppercase
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# that match <ctype.h>'s definitions.
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try:
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from strop import maketrans, lowercase, uppercase, whitespace
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letters = lowercase + uppercase
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except ImportError:
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pass # Use the original versions
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