# 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

"""

# 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 = map(None, _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