mirror of
https://github.com/python/cpython.git
synced 2025-07-13 22:35:18 +00:00
8bee76106e
This patch includes test cases and documentation updates, as well as NEWS file updates. This patch also updates the sre modules so that they don't import the string module, breaking direct circular imports.
466 lines
14 KiB
Python
466 lines
14 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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# Note that Cookie.py bogusly uses _idmap :(
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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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# See also regsub.capwords().
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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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import re as _re
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class Template(unicode):
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"""A string class for supporting $-substitutions."""
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__slots__ = []
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# Search for $$, $identifier, ${identifier}, and any bare $'s
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pattern = _re.compile(r"""
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# Match exactly two $'s -- this is the escape sequence
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(?P<escaped>\${2})|
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# Match a $ followed by a Python identifier
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\$(?P<named>[_a-z][_a-z0-9]*)|
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# Match a $ followed by a brace delimited identifier
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\${(?P<braced>[_a-z][_a-z0-9]*)}|
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# Match any other $'s
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(?P<bogus>\$)
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""", _re.IGNORECASE | _re.VERBOSE)
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def __mod__(self, mapping):
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def convert(mo):
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groups = mo.groupdict()
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if groups.get('escaped') is not None:
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return '$'
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if groups.get('bogus') is not None:
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raise ValueError('Invalid placeholder at index %d' %
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mo.start('bogus'))
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val = mapping[groups.get('named') or groups.get('braced')]
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return unicode(val)
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return self.pattern.sub(convert, self)
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class SafeTemplate(Template):
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"""A string class for supporting $-substitutions.
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This class is 'safe' in the sense that you will never get KeyErrors if
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there are placeholders missing from the interpolation dictionary. In that
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case, you will get the original placeholder in the value string.
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"""
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__slots__ = []
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def __mod__(self, mapping):
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def convert(mo):
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groups = mo.groupdict()
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if groups.get('escaped') is not None:
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return '$'
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if groups.get('bogus') is not None:
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raise ValueError('Invalid placeholder at index %d' %
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mo.start('bogus'))
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named = groups.get('named')
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if named is not None:
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try:
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return unicode(mapping[named])
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except KeyError:
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return '$' + named
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braced = groups.get('braced')
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try:
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return unicode(mapping[braced])
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except KeyError:
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return '${' + braced + '}'
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return self.pattern.sub(convert, self)
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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, 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 = long
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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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