# module 'string' -- A collection of string operations # 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. """Common string manipulations. 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 """ from warnings import warnpy3k warnpy3k("the stringold module has been removed in Python 3.0", stacklevel=2) del warnpy3k # 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' # 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 def split(s, sep=None, maxsplit=0): """split(str [,sep [,maxsplit]]) -> list of strings Return a list of the words in the string s, using sep as the delimiter string. If maxsplit is nonzero, splits into at most maxsplit words If sep is not specified, any whitespace string is a separator. Maxsplit defaults to 0. (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 # for a little bit of speed _apply = apply # 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 _apply(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 _apply(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 _apply(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 _apply(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 _apply(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. """ if type(s) == _StringType: return _float(s) else: raise TypeError('argument 1: expected string, %s found' % type(s).__name__) # Convert string to integer def atoi(*args): """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. """ try: s = args[0] except IndexError: raise TypeError('function requires at least 1 argument: %d given' % len(args)) # Don't catch type error resulting from too many arguments to int(). The # error message isn't compatible but the error type is, and this function # is complicated enough already. if type(s) == _StringType: return _apply(_int, args) else: raise TypeError('argument 1: expected string, %s found' % type(s).__name__) # Convert string to long integer def atol(*args): """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. """ try: s = args[0] except IndexError: raise TypeError('function requires at least 1 argument: %d given' % len(args)) # Don't catch type error resulting from too many arguments to long(). The # error message isn't compatible but the error type is, and this function # is complicated enough already. if type(s) == _StringType: return _apply(_long, args) else: raise TypeError('argument 1: expected string, %s found' % type(s).__name__) # 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. """ n = width - len(s) if n <= 0: return s return s + ' '*n # 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. """ n = width - len(s) if n <= 0: return s return ' '*n + s # 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. """ n = width - len(s) if n <= 0: return s half = n/2 if n%2 and width%2: # This ensures that center(center(s, i), j) = center(s, j) half = half+1 return ' '*half + s + ' '*(n-half) # 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 = repr(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). """ res = line = '' for c in s: if c == '\t': c = ' '*(tabsize - len(line) % tabsize) line = line + c if c == '\n': res = res + line line = '' return res + line # 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". 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 = list(_idmap) L = _idmapL[:] fromstr = map(ord, fromstr) for i in range(len(fromstr)): L[fromstr[i]] = tostr[i] return join(L, "") # Substring replacement (global) def replace(s, old, new, maxsplit=0): """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) # XXX: transitional # # If string objects do not have methods, then we need to use the old string.py # library, which uses strop for many more things than just the few outlined # below. try: ''.upper except AttributeError: from stringold import * # 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