Initial revision
diff --git a/Lib/string.py b/Lib/string.py
new file mode 100644
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+++ b/Lib/string.py
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+# module 'string' -- A collection of string operations
+
+# XXX Some of these operations are incredibly slow and should be built in
+
+# Some strings for ctype-style character classification
+whitespace = ' \t\n'
+lowercase = 'abcdefghijklmnopqrstuvwxyz'
+uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+letters = lowercase + uppercase
+digits = '0123456789'
+hexdigits = digits + 'abcdef' + 'ABCDEF'
+octdigits = '01234567'
+
+# Case conversion helpers
+_caseswap = {}
+for i in range(26):
+ _caseswap[lowercase[i]] = uppercase[i]
+ _caseswap[uppercase[i]] = lowercase[i]
+del i
+
+# convert UPPER CASE letters to lower case
+def lower(s):
+ res = ''
+ for c in s:
+ if 'A' <= c <= 'Z': c = _caseswap[c]
+ res = res + c
+ return res
+
+# Convert lower case letters to UPPER CASE
+def upper(s):
+ res = ''
+ for c in s:
+ if 'a' <= c <= 'z': c = _caseswap[c]
+ res = res + c
+ return res
+
+# Swap lower case letters and UPPER CASE
+def swapcase(s):
+ res = ''
+ for c in s:
+ if 'a' <= c <= 'z' or 'A' <= c <= 'Z': c = _caseswap[c]
+ res = res + c
+ return res
+
+# Strip leading and trailing tabs and spaces
+def strip(s):
+ i, j = 0, len(s)
+ while i < j and s[i] in whitespace: i = i+1
+ while i < j and s[j-1] in whitespace: j = j-1
+ return s[i:j]
+
+# Split a string into a list of space/tab-separated words
+# NB: split(s) is NOT the same as splitfields(s, ' ')!
+def split(s):
+ res = []
+ i, n = 0, len(s)
+ while i < n:
+ while i < n and s[i] in whitespace: i = i+1
+ if i = n: break
+ j = i
+ while j < n and s[j] not in whitespace: j = j+1
+ res.append(s[i:j])
+ i = j
+ return res
+
+# Split a list into fields separated by a given string
+# NB: splitfields(s, ' ') is NOT the same as split(s)!
+def splitfields(s, sep):
+ res = []
+ ns = len(s)
+ nsep = len(sep)
+ i = j = 0
+ while j+nsep <= ns:
+ if s[j:j+nsep] = sep:
+ res.append(s[i:j])
+ i = j = j + nsep
+ else:
+ j = j + 1
+ res.append(s[i:])
+ return res
+
+# Find substring
+index_error = 'substring not found in string.index'
+def index(s, sub):
+ n = len(sub)
+ for i in range(len(s) - n):
+ if sub = s[i:i+n]: return i
+ raise index_error, (s, sub)
+
+# Convert string to integer
+atoi_error = 'non-numeric argument to string.atoi'
+def atoi(str):
+ s = str
+ if s[:1] in '+-': s = s[1:]
+ if not s: raise atoi_error, str
+ for c in s:
+ if c not in digits: raise atoi_error, str
+ return eval(str)
+
+# Left-justify a string
+def ljust(s, width):
+ n = len(s)
+ if n >= width: return s
+ return s + ' '*(width-n)
+
+# Right-justify a string
+def rjust(s, width):
+ n = len(s)
+ if n >= width: return s
+ return ' '*(width-n) + s
+
+# Center a string
+def center(s, width):
+ n = len(s)
+ if n >= width: return s
+ return ' '*((width-n)/2) + s + ' '*(width -(width-n)/2)
+
+# 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):
+ if type(x) = type(''): s = x
+ else: s = `x`
+ n = len(s)
+ if n >= width: return s
+ sign = ''
+ if s[0] = '-':
+ sign, s = '-', s[1:]
+ return sign + '0'*(width-n) + s