mirror of https://github.com/python/cpython.git
148 lines
3.3 KiB
Python
148 lines
3.3 KiB
Python
# module 'string' -- A collection of string operations
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# XXX Some of these operations are incredibly slow and should be built in
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# Some strings for ctype-style character classification
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whitespace = ' \t\n'
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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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_caseswap = {}
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for i in range(26):
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_caseswap[lowercase[i]] = uppercase[i]
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_caseswap[uppercase[i]] = lowercase[i]
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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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if 'A' <= c <= 'Z': c = _caseswap[c]
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res = res + 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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if 'a' <= c <= 'z': c = _caseswap[c]
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res = res + 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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if 'a' <= c <= 'z' or 'A' <= c <= 'Z': c = _caseswap[c]
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res = res + 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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def splitfields(s, sep):
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res = []
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ns = len(s)
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nsep = len(sep)
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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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res = ''
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for w in words:
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res = res + (' ' + w)
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return res[1:]
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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
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index_error = 'substring not found in string.index'
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def index(s, sub):
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n = len(sub)
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for i in range(len(s) + 1 - n):
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if sub == s[i:i+n]: return i
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raise index_error, (s, sub)
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# Convert string to integer
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atoi_error = 'non-numeric argument to string.atoi'
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def atoi(str):
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s = str
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if s[:1] in '+-': s = s[1:]
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if not s: raise atoi_error, str
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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(str)
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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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