Lib/string.py - platform/external/python/cpython2 - Gitiles

 """A collection of string operations (most are no longer used in Python 1.6).

 Warning: most of the code you see here isn't normally used nowadays.  With
 Python 1.6, many of these functions are implemented as methods on the
 standard string object. They used to be implemented by a built-in module
 called strop, but strop is now obsolete itself.

 Public module variables:

 whitespace -- a string containing all characters considered whitespace
 lowercase -- a string containing all characters considered lowercase letters
 uppercase -- a string containing all characters considered uppercase letters
 letters -- a string containing all characters considered letters
 digits -- a string containing all characters considered decimal digits
 hexdigits -- a string containing all characters considered hexadecimal digits
 octdigits -- a string containing all characters considered octal digits
 punctuation -- a string containing all characters considered punctuation
 printable -- a string containing all characters considered printable

 """

 # Some strings for ctype-style character classification
 whitespace = ' \t\n\r\v\f'
 lowercase = 'abcdefghijklmnopqrstuvwxyz'
 uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
 letters = lowercase + uppercase
 digits = '0123456789'
 hexdigits = digits + 'abcdef' + 'ABCDEF'
 octdigits = '01234567'
 punctuation = """!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
 printable = digits + letters + punctuation + whitespace

 # Case conversion helpers
 _idmap = ''
 for i in range(256): _idmap = _idmap + chr(i)
 del i

 # Backward compatible names for exceptions
 index_error = ValueError
 atoi_error = ValueError
 atof_error = ValueError
 atol_error = ValueError

 # convert UPPER CASE letters to lower case
 def lower(s):
     """lower(s) -> string

     Return a copy of the string s converted to lowercase.

     """
     return s.lower()

 # Convert lower case letters to UPPER CASE
 def upper(s):
     """upper(s) -> string

     Return a copy of the string s converted to uppercase.

     """
     return s.upper()

 # Swap lower case letters and UPPER CASE
 def swapcase(s):
     """swapcase(s) -> string

     Return a copy of the string s with upper case characters
     converted to lowercase and vice versa.

     """
     return s.swapcase()

 # Strip leading and trailing tabs and spaces
 def strip(s):
     """strip(s) -> string

     Return a copy of the string s with leading and trailing
     whitespace removed.

     """
     return s.strip()

 # Strip leading tabs and spaces
 def lstrip(s):
     """lstrip(s) -> string

     Return a copy of the string s with leading whitespace removed.

     """
     return s.lstrip()

 # Strip trailing tabs and spaces
 def rstrip(s):
     """rstrip(s) -> string

     Return a copy of the string s with trailing whitespace
     removed.

     """
     return s.rstrip()


 # Split a string into a list of space/tab-separated words
 # NB: split(s) is NOT the same as splitfields(s, ' ')!
 def split(s, sep=None, maxsplit=-1):
     """split(s [,sep [,maxsplit]]) -> list of strings

     Return a list of the words in the string s, using sep as the
     delimiter string.  If maxsplit is given, splits into at most
     maxsplit words.  If sep is not specified, any whitespace string
     is a separator.

     (split and splitfields are synonymous)

     """
     return s.split(sep, maxsplit)
 splitfields = split

 # Join fields with optional separator
 def join(words, sep = ' '):
     """join(list [,sep]) -> string

     Return a string composed of the words in list, with
     intervening occurrences of sep.  The default separator is a
     single space.

     (joinfields and join are synonymous)

     """
     return sep.join(words)
 joinfields = join

 # Find substring, raise exception if not found
 def index(s, *args):
     """index(s, sub [,start [,end]]) -> int

     Like find but raises ValueError when the substring is not found.

     """
     return s.index(*args)

 # Find last substring, raise exception if not found
 def rindex(s, *args):
     """rindex(s, sub [,start [,end]]) -> int

     Like rfind but raises ValueError when the substring is not found.

     """
     return s.rindex(*args)

 # Count non-overlapping occurrences of substring
 def count(s, *args):
     """count(s, sub[, start[,end]]) -> int

     Return the number of occurrences of substring sub in string
     s[start:end].  Optional arguments start and end are
     interpreted as in slice notation.

     """
     return s.count(*args)

 # Find substring, return -1 if not found
 def find(s, *args):
     """find(s, sub [,start [,end]]) -> in

     Return the lowest index in s where substring sub is found,
     such that sub is contained within s[start,end].  Optional
     arguments start and end are interpreted as in slice notation.

     Return -1 on failure.

     """
     return s.find(*args)

 # Find last substring, return -1 if not found
 def rfind(s, *args):
     """rfind(s, sub [,start [,end]]) -> int

     Return the highest index in s where substring sub is found,
     such that sub is contained within s[start,end].  Optional
     arguments start and end are interpreted as in slice notation.

     Return -1 on failure.

     """
     return s.rfind(*args)

 # for a bit of speed
 _float = float
 _int = int
 _long = long
 _StringType = type('')

 # Convert string to float
 def atof(s):
     """atof(s) -> float

     Return the floating point number represented by the string s.

     """
     return _float(s)


 # Convert string to integer
 def atoi(s , base=10):
     """atoi(s [,base]) -> int

     Return the integer represented by the string s in the given
     base, which defaults to 10.  The string s must consist of one
     or more digits, possibly preceded by a sign.  If base is 0, it
     is chosen from the leading characters of s, 0 for octal, 0x or
     0X for hexadecimal.  If base is 16, a preceding 0x or 0X is
     accepted.

     """
     return _int(s, base)


 # Convert string to long integer
 def atol(s, base=10):
     """atol(s [,base]) -> long

     Return the long integer represented by the string s in the
     given base, which defaults to 10.  The string s must consist
     of one or more digits, possibly preceded by a sign.  If base
     is 0, it is chosen from the leading characters of s, 0 for
     octal, 0x or 0X for hexadecimal.  If base is 16, a preceding
     0x or 0X is accepted.  A trailing L or l is not accepted,
     unless base is 0.

     """
     return _long(s, base)


 # Left-justify a string
 def ljust(s, width):
     """ljust(s, width) -> string

     Return a left-justified version of s, in a field of the
     specified width, padded with spaces as needed.  The string is
     never truncated.

     """
     return s.ljust(width)

 # Right-justify a string
 def rjust(s, width):
     """rjust(s, width) -> string

     Return a right-justified version of s, in a field of the
     specified width, padded with spaces as needed.  The string is
     never truncated.

     """
     return s.rjust(width)

 # Center a string
 def center(s, width):
     """center(s, width) -> string

     Return a center version of s, in a field of the specified
     width. padded with spaces as needed.  The string is never
     truncated.

     """
     return s.center(width)

 # Zero-fill a number, e.g., (12, 3) --> '012' and (-3, 3) --> '-03'
 # Decadent feature: the argument may be a string or a number
 # (Use of this is deprecated; it should be a string as with ljust c.s.)
 def zfill(x, width):
     """zfill(x, width) -> string

     Pad a numeric string x with zeros on the left, to fill a field
     of the specified width.  The string x is never truncated.

     """
     if type(x) == type(''): s = x
     else: s = `x`
     n = len(s)
     if n >= width: return s
     sign = ''
     if s[0] in ('-', '+'):
         sign, s = s[0], s[1:]
     return sign + '0'*(width-n) + s

 # Expand tabs in a string.
 # Doesn't take non-printing chars into account, but does understand \n.
 def expandtabs(s, tabsize=8):
     """expandtabs(s [,tabsize]) -> string

     Return a copy of the string s with all tab characters replaced
     by the appropriate number of spaces, depending on the current
     column, and the tabsize (default 8).

     """
     return s.expandtabs(tabsize)

 # Character translation through look-up table.
 def translate(s, table, deletions=""):
     """translate(s,table [,deletechars]) -> string

     Return a copy of the string s, where all characters occurring
     in the optional argument deletechars are removed, and the
     remaining characters have been mapped through the given
     translation table, which must be a string of length 256.

     """
     return s.translate(table, deletions)

 # Capitalize a string, e.g. "aBc  dEf" -> "Abc  def".
 def capitalize(s):
     """capitalize(s) -> string

     Return a copy of the string s with only its first character
     capitalized.

     """
     return s.capitalize()

 # Capitalize the words in a string, e.g. " aBc  dEf " -> "Abc Def".
 # See also regsub.capwords().
 def capwords(s, sep=None):
     """capwords(s, [sep]) -> string

     Split the argument into words using split, capitalize each
     word using capitalize, and join the capitalized words using
     join. Note that this replaces runs of whitespace characters by
     a single space.

     """
     return join(map(capitalize, s.split(sep)), sep or ' ')

 # Construct a translation string
 _idmapL = None
 def maketrans(fromstr, tostr):
     """maketrans(frm, to) -> string

     Return a translation table (a string of 256 bytes long)
     suitable for use in string.translate.  The strings frm and to
     must be of the same length.

     """
     if len(fromstr) != len(tostr):
         raise ValueError, "maketrans arguments must have same length"
     global _idmapL
     if not _idmapL:
         _idmapL = map(None, _idmap)
     L = _idmapL[:]
     fromstr = map(ord, fromstr)
     for i in range(len(fromstr)):
         L[fromstr[i]] = tostr[i]
     return joinfields(L, "")

 # Substring replacement (global)
 def replace(s, old, new, maxsplit=-1):
     """replace (str, old, new[, maxsplit]) -> string

     Return a copy of string str with all occurrences of substring
     old replaced by new. If the optional argument maxsplit is
     given, only the first maxsplit occurrences are replaced.

     """
     return s.replace(old, new, maxsplit)


 # Try importing optional built-in module "strop" -- if it exists,
 # it redefines some string operations that are 100-1000 times faster.
 # It also defines values for whitespace, lowercase and uppercase
 # that match <ctype.h>'s definitions.

 try:
     from strop import maketrans, lowercase, uppercase, whitespace
     letters = lowercase + uppercase
 except ImportError:
     pass                                          # Use the original versions
	"""A collection of string operations (most are no longer used in Python 1.6).

	Warning: most of the code you see here isn't normally used nowadays. With
	Python 1.6, many of these functions are implemented as methods on the
	standard string object. They used to be implemented by a built-in module
	called strop, but strop is now obsolete itself.

	Public module variables:

	whitespace -- a string containing all characters considered whitespace
	lowercase -- a string containing all characters considered lowercase letters
	uppercase -- a string containing all characters considered uppercase letters
	letters -- a string containing all characters considered letters
	digits -- a string containing all characters considered decimal digits
	hexdigits -- a string containing all characters considered hexadecimal digits
	octdigits -- a string containing all characters considered octal digits
	punctuation -- a string containing all characters considered punctuation
	printable -- a string containing all characters considered printable

	"""

	# Some strings for ctype-style character classification
	whitespace = ' \t\n\r\v\f'
	lowercase = 'abcdefghijklmnopqrstuvwxyz'
	uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
	letters = lowercase + uppercase
	digits = '0123456789'
	hexdigits = digits + 'abcdef' + 'ABCDEF'
	octdigits = '01234567'
	punctuation = """!"#$%&'()*+,-./:;<=>?@[\]^_`{\|}~"""
	printable = digits + letters + punctuation + whitespace

	# Case conversion helpers
	_idmap = ''
	for i in range(256): _idmap = _idmap + chr(i)
	del i

	# Backward compatible names for exceptions
	index_error = ValueError
	atoi_error = ValueError
	atof_error = ValueError
	atol_error = ValueError

	# convert UPPER CASE letters to lower case
	def lower(s):
	"""lower(s) -> string

	Return a copy of the string s converted to lowercase.

	"""
	return s.lower()

	# Convert lower case letters to UPPER CASE
	def upper(s):
	"""upper(s) -> string

	Return a copy of the string s converted to uppercase.

	"""
	return s.upper()

	# Swap lower case letters and UPPER CASE
	def swapcase(s):
	"""swapcase(s) -> string

	Return a copy of the string s with upper case characters
	converted to lowercase and vice versa.

	"""
	return s.swapcase()

	# Strip leading and trailing tabs and spaces
	def strip(s):
	"""strip(s) -> string

	Return a copy of the string s with leading and trailing
	whitespace removed.

	"""
	return s.strip()

	# Strip leading tabs and spaces
	def lstrip(s):
	"""lstrip(s) -> string

	Return a copy of the string s with leading whitespace removed.

	"""
	return s.lstrip()

	# Strip trailing tabs and spaces
	def rstrip(s):
	"""rstrip(s) -> string

	Return a copy of the string s with trailing whitespace
	removed.

	"""
	return s.rstrip()


	# Split a string into a list of space/tab-separated words
	# NB: split(s) is NOT the same as splitfields(s, ' ')!
	def split(s, sep=None, maxsplit=-1):
	"""split(s [,sep [,maxsplit]]) -> list of strings

	Return a list of the words in the string s, using sep as the
	delimiter string. If maxsplit is given, splits into at most
	maxsplit words. If sep is not specified, any whitespace string
	is a separator.

	(split and splitfields are synonymous)

	"""
	return s.split(sep, maxsplit)
	splitfields = split

	# Join fields with optional separator
	def join(words, sep = ' '):
	"""join(list [,sep]) -> string

	Return a string composed of the words in list, with
	intervening occurrences of sep. The default separator is a
	single space.

	(joinfields and join are synonymous)

	"""
	return sep.join(words)
	joinfields = join

	# Find substring, raise exception if not found
	def index(s, *args):
	"""index(s, sub [,start [,end]]) -> int

	Like find but raises ValueError when the substring is not found.

	"""
	return s.index(*args)

	# Find last substring, raise exception if not found
	def rindex(s, *args):
	"""rindex(s, sub [,start [,end]]) -> int

	Like rfind but raises ValueError when the substring is not found.

	"""
	return s.rindex(*args)

	# Count non-overlapping occurrences of substring
	def count(s, *args):
	"""count(s, sub[, start[,end]]) -> int

	Return the number of occurrences of substring sub in string
	s[start:end]. Optional arguments start and end are
	interpreted as in slice notation.

	"""
	return s.count(*args)

	# Find substring, return -1 if not found
	def find(s, *args):
	"""find(s, sub [,start [,end]]) -> in

	Return the lowest index in s where substring sub is found,
	such that sub is contained within s[start,end]. Optional
	arguments start and end are interpreted as in slice notation.

	Return -1 on failure.

	"""
	return s.find(*args)

	# Find last substring, return -1 if not found
	def rfind(s, *args):
	"""rfind(s, sub [,start [,end]]) -> int

	Return the highest index in s where substring sub is found,
	such that sub is contained within s[start,end]. Optional
	arguments start and end are interpreted as in slice notation.

	Return -1 on failure.

	"""
	return s.rfind(*args)

	# for a bit of speed
	_float = float
	_int = int
	_long = long
	_StringType = type('')

	# Convert string to float
	def atof(s):
	"""atof(s) -> float

	Return the floating point number represented by the string s.

	"""
	return _float(s)


	# Convert string to integer
	def atoi(s , base=10):
	"""atoi(s [,base]) -> int

	Return the integer represented by the string s in the given
	base, which defaults to 10. The string s must consist of one
	or more digits, possibly preceded by a sign. If base is 0, it
	is chosen from the leading characters of s, 0 for octal, 0x or
	0X for hexadecimal. If base is 16, a preceding 0x or 0X is
	accepted.

	"""
	return _int(s, base)


	# Convert string to long integer
	def atol(s, base=10):
	"""atol(s [,base]) -> long

	Return the long integer represented by the string s in the
	given base, which defaults to 10. The string s must consist
	of one or more digits, possibly preceded by a sign. If base
	is 0, it is chosen from the leading characters of s, 0 for
	octal, 0x or 0X for hexadecimal. If base is 16, a preceding
	0x or 0X is accepted. A trailing L or l is not accepted,
	unless base is 0.

	"""
	return _long(s, base)


	# Left-justify a string
	def ljust(s, width):
	"""ljust(s, width) -> string

	Return a left-justified version of s, in a field of the
	specified width, padded with spaces as needed. The string is
	never truncated.

	"""
	return s.ljust(width)

	# Right-justify a string
	def rjust(s, width):
	"""rjust(s, width) -> string

	Return a right-justified version of s, in a field of the
	specified width, padded with spaces as needed. The string is
	never truncated.

	"""
	return s.rjust(width)

	# Center a string
	def center(s, width):
	"""center(s, width) -> string

	Return a center version of s, in a field of the specified
	width. padded with spaces as needed. The string is never
	truncated.

	"""
	return s.center(width)

	# Zero-fill a number, e.g., (12, 3) --> '012' and (-3, 3) --> '-03'
	# Decadent feature: the argument may be a string or a number
	# (Use of this is deprecated; it should be a string as with ljust c.s.)
	def zfill(x, width):
	"""zfill(x, width) -> string

	Pad a numeric string x with zeros on the left, to fill a field
	of the specified width. The string x is never truncated.

	"""
	if type(x) == type(''): s = x
	else: s = `x`
	n = len(s)
	if n >= width: return s
	sign = ''
	if s[0] in ('-', '+'):
	sign, s = s[0], s[1:]
	return sign + '0'*(width-n) + s

	# Expand tabs in a string.
	# Doesn't take non-printing chars into account, but does understand \n.
	def expandtabs(s, tabsize=8):
	"""expandtabs(s [,tabsize]) -> string

	Return a copy of the string s with all tab characters replaced
	by the appropriate number of spaces, depending on the current
	column, and the tabsize (default 8).

	"""
	return s.expandtabs(tabsize)

	# Character translation through look-up table.
	def translate(s, table, deletions=""):
	"""translate(s,table [,deletechars]) -> string

	Return a copy of the string s, where all characters occurring
	in the optional argument deletechars are removed, and the
	remaining characters have been mapped through the given
	translation table, which must be a string of length 256.

	"""
	return s.translate(table, deletions)

	# Capitalize a string, e.g. "aBc dEf" -> "Abc def".
	def capitalize(s):
	"""capitalize(s) -> string

	Return a copy of the string s with only its first character
	capitalized.

	"""
	return s.capitalize()

	# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
	# See also regsub.capwords().
	def capwords(s, sep=None):
	"""capwords(s, [sep]) -> string

	Split the argument into words using split, capitalize each
	word using capitalize, and join the capitalized words using
	join. Note that this replaces runs of whitespace characters by
	a single space.

	"""
	return join(map(capitalize, s.split(sep)), sep or ' ')

	# Construct a translation string
	_idmapL = None
	def maketrans(fromstr, tostr):
	"""maketrans(frm, to) -> string

	Return a translation table (a string of 256 bytes long)
	suitable for use in string.translate. The strings frm and to
	must be of the same length.

	"""
	if len(fromstr) != len(tostr):
	raise ValueError, "maketrans arguments must have same length"
	global _idmapL
	if not _idmapL:
	_idmapL = map(None, _idmap)
	L = _idmapL[:]
	fromstr = map(ord, fromstr)
	for i in range(len(fromstr)):
	L[fromstr[i]] = tostr[i]
	return joinfields(L, "")

	# Substring replacement (global)
	def replace(s, old, new, maxsplit=-1):
	"""replace (str, old, new[, maxsplit]) -> string

	Return a copy of string str with all occurrences of substring
	old replaced by new. If the optional argument maxsplit is
	given, only the first maxsplit occurrences are replaced.

	"""
	return s.replace(old, new, maxsplit)


	# Try importing optional built-in module "strop" -- if it exists,
	# it redefines some string operations that are 100-1000 times faster.
	# It also defines values for whitespace, lowercase and uppercase
	# that match <ctype.h>'s definitions.

	try:
	from strop import maketrans, lowercase, uppercase, whitespace
	letters = lowercase + uppercase
	except ImportError:
	pass # Use the original versions