281 lines
6.4 KiB
Python
281 lines
6.4 KiB
Python
# module 'string' -- A collection of string operations
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# Warning: most of the code you see here isn't normally used nowadays.
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# At the end of this file most functions are replaced by built-in
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# functions imported from built-in module "strop".
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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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digits = '0123456789'
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hexdigits = digits + 'abcdef' + 'ABCDEF'
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octdigits = '01234567'
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# Case conversion helpers
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_idmap = ''
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for i in range(256): _idmap = _idmap + chr(i)
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_lower = _idmap[:ord('A')] + lowercase + _idmap[ord('Z')+1:]
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_upper = _idmap[:ord('a')] + uppercase + _idmap[ord('z')+1:]
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_swapcase = _upper[:ord('A')] + lowercase + _upper[ord('Z')+1:]
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del i
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# convert UPPER CASE letters to lower case
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def lower(s):
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res = ''
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for c in s:
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res = res + _lower[ord(c)]
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return res
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# Convert lower case letters to UPPER CASE
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def upper(s):
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res = ''
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for c in s:
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res = res + _upper[ord(c)]
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return res
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# Swap lower case letters and UPPER CASE
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def swapcase(s):
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res = ''
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for c in s:
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res = res + _swapcase[ord(c)]
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return res
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# Strip leading and trailing tabs and spaces
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def strip(s):
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i, j = 0, len(s)
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while i < j and s[i] in whitespace: i = i+1
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while i < j and s[j-1] in whitespace: j = j-1
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return s[i:j]
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# Split a string into a list of space/tab-separated words
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# NB: split(s) is NOT the same as splitfields(s, ' ')!
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def split(s):
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res = []
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i, n = 0, len(s)
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while i < n:
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while i < n and s[i] in whitespace: i = i+1
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if i == n: break
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j = i
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while j < n and s[j] not in whitespace: j = j+1
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res.append(s[i:j])
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i = j
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return res
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# Split a list into fields separated by a given string
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# NB: splitfields(s, ' ') is NOT the same as split(s)!
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# splitfields(s, '') returns [s] (in analogy with split() in nawk)
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def splitfields(s, sep):
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res = []
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nsep = len(sep)
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if nsep == 0:
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return [s]
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ns = len(s)
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i = j = 0
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while j+nsep <= ns:
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if s[j:j+nsep] == sep:
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res.append(s[i:j])
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i = j = j + nsep
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else:
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j = j + 1
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res.append(s[i:])
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return res
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# Join words with spaces between them
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def join(words):
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return joinfields(words, ' ')
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# Join fields with separator
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def joinfields(words, sep):
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res = ''
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for w in words:
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res = res + (sep + w)
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return res[len(sep):]
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# Find substring, raise exception if not found
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index_error = 'substring not found in string.index'
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def index(s, sub, i = 0):
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if i < 0: i = i + len(s)
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n = len(sub)
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m = len(s) + 1 - n
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while i < m:
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if sub == s[i:i+n]: return i
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i = i+1
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raise index_error, (s, sub, i)
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# Find last substring, raise exception if not found
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def rindex(s, sub, i = 0):
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if i < 0: i = i + len(s)
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n = len(sub)
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m = len(s) + 1 - n
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r = None
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while i < m:
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if sub == s[i:i+n]: r = i
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i = i+1
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if r is None:
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raise index_error, (s, sub, i)
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return r
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# Count non-overlapping occurrences of substring
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def count(s, sub, i = 0):
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if i < 0: i = i + len(s)
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n = len(sub)
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m = len(s) + 1 - n
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if n == 0: return m-i
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r = 0
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while i < m:
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if sub == s[i:i+n]:
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r = r+1
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i = i+n
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else:
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i = i+1
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return r
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# Find substring, return -1 if not found
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def find(s, sub, i = 0):
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try:
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return index(s, sub, i)
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except index_error:
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return -1
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# Find last substring, return -1 if not found
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def rfind(s, sub, i = 0):
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try:
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return rindex(s, sub, i)
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except index_error:
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return -1
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# Convert string to float
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atof_error = 'non-float argument to string.atof'
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def atof(str):
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import regex
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sign = ''
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s = str
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if s and s[0] in '+-':
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sign = s[0]
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s = s[1:]
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if not s: raise atof_error, str
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while s[0] == '0' and len(s) > 1 and s[1] in digits: s = s[1:]
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if regex.match('[0-9]*\(\.[0-9]*\)?\([eE][-+]?[0-9]+\)?', s) != len(s):
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raise atof_error, str
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try:
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return float(eval(sign + s))
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except SyntaxError:
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raise atof_error, str
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# Convert string to integer
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atoi_error = 'non-integer argument to string.atoi'
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def atoi(str):
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sign = ''
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s = str
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if s and s[0] in '+-':
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sign = s[0]
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s = s[1:]
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if not s: raise atoi_error, str
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while s[0] == '0' and len(s) > 1: s = s[1:]
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for c in s:
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if c not in digits: raise atoi_error, str
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return eval(sign + s)
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# Convert string to long integer
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atol_error = 'non-integer argument to string.atol'
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def atol(str):
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sign = ''
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s = str
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if s and s[0] in '+-':
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sign = s[0]
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s = s[1:]
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if not s: raise atoi_error, str
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while s[0] == '0' and len(s) > 1: s = s[1:]
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for c in s:
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if c not in digits: raise atoi_error, str
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return eval(sign + s + 'L')
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# Left-justify a string
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def ljust(s, width):
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n = width - len(s)
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if n <= 0: return s
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return s + ' '*n
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# Right-justify a string
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def rjust(s, width):
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n = width - len(s)
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if n <= 0: return s
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return ' '*n + s
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# Center a string
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def center(s, width):
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n = width - len(s)
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if n <= 0: return s
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half = n/2
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if n%2 and width%2:
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# This ensures that center(center(s, i), j) = center(s, j)
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half = half+1
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return ' '*half + s + ' '*(n-half)
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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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if type(x) == type(''): s = x
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else: s = `x`
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n = len(s)
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if n >= width: return s
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sign = ''
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if s[0] in ('-', '+'):
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sign, s = s[0], s[1:]
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return sign + '0'*(width-n) + s
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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):
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res = line = ''
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for c in s:
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if c == '\t':
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c = ' '*(tabsize - len(line)%tabsize)
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line = line + c
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if c == '\n':
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res = res + line
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line = ''
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return res + line
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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 *
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letters = lowercase + uppercase
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except ImportError:
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pass # Use the original, slow versions
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# If certain functions are found, redefine the corresponding exceptions
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# as ValueError
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try:
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from strop import index
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index_error = ValueError
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except ImportError:
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pass # Use the original, slow versions
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try:
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from strop import atoi
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atoi_error = ValueError
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except ImportError:
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pass # Use the original, slow versions
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try:
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from strop import atof
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atof_error = ValueError
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except ImportError:
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pass # Use the original, slow versions
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try:
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from strop import atol
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atol_error = ValueError
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except ImportError:
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pass # Use the original, slow versions
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