mirror of https://github.com/python/cpython
275 lines
6.7 KiB
Python
275 lines
6.7 KiB
Python
# module 'string' -- A collection of string operations
|
|
|
|
# Warning: most of the code you see here isn't normally used nowadays.
|
|
# At the end of this file most functions are replaced by built-in
|
|
# functions imported from built-in module "strop".
|
|
|
|
# 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)
|
|
_lower = _idmap[:ord('A')] + lowercase + _idmap[ord('Z')+1:]
|
|
_upper = _idmap[:ord('a')] + uppercase + _idmap[ord('z')+1:]
|
|
_swapcase = _upper[:ord('A')] + lowercase + _upper[ord('Z')+1:]
|
|
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):
|
|
res = ''
|
|
for c in s:
|
|
res = res + _lower[ord(c)]
|
|
return res
|
|
|
|
# Convert lower case letters to UPPER CASE
|
|
def upper(s):
|
|
res = ''
|
|
for c in s:
|
|
res = res + _upper[ord(c)]
|
|
return res
|
|
|
|
# Swap lower case letters and UPPER CASE
|
|
def swapcase(s):
|
|
res = ''
|
|
for c in s:
|
|
res = res + _swapcase[ord(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, sep=None):
|
|
if sep is not None: return splitfields(s, sep)
|
|
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)!
|
|
# splitfields(s, '') returns [s] (in analogy with split() in nawk)
|
|
def splitfields(s, sep=None):
|
|
if sep is None: return split(s)
|
|
res = []
|
|
nsep = len(sep)
|
|
if nsep == 0:
|
|
return [s]
|
|
ns = len(s)
|
|
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
|
|
|
|
# Join words with spaces between them
|
|
def join(words, sep = ' '):
|
|
return joinfields(words, sep)
|
|
|
|
# Join fields with optional separator
|
|
def joinfields(words, sep = ' '):
|
|
res = ''
|
|
for w in words:
|
|
res = res + (sep + w)
|
|
return res[len(sep):]
|
|
|
|
# Find substring, raise exception if not found
|
|
def index(s, sub, i = 0):
|
|
res = find(s, sub, i)
|
|
if res < 0:
|
|
raise ValueError, 'substring not found in string.index'
|
|
return res
|
|
|
|
# Find last substring, raise exception if not found
|
|
def rindex(s, sub, i = 0):
|
|
res = rfind(s, sub, i)
|
|
if res < 0:
|
|
raise ValueError, 'substring not found in string.index'
|
|
return res
|
|
|
|
# Count non-overlapping occurrences of substring
|
|
def count(s, sub, i = 0):
|
|
if i < 0: i = max(0, i + len(s))
|
|
n = len(sub)
|
|
m = len(s) + 1 - n
|
|
if n == 0: return m-i
|
|
r = 0
|
|
while i < m:
|
|
if sub == s[i:i+n]:
|
|
r = r+1
|
|
i = i+n
|
|
else:
|
|
i = i+1
|
|
return r
|
|
|
|
# Find substring, return -1 if not found
|
|
def find(s, sub, i = 0):
|
|
if i < 0: i = max(0, i + len(s))
|
|
n = len(sub)
|
|
m = len(s) + 1 - n
|
|
while i < m:
|
|
if sub == s[i:i+n]: return i
|
|
i = i+1
|
|
return -1
|
|
|
|
# Find last substring, return -1 if not found
|
|
def rfind(s, sub, i = 0):
|
|
if i < 0: i = max(0, i + len(s))
|
|
n = len(sub)
|
|
m = len(s) + 1 - n
|
|
r = -1
|
|
while i < m:
|
|
if sub == s[i:i+n]: r = i
|
|
i = i+1
|
|
return r
|
|
|
|
# Convert string to float
|
|
def atof(str):
|
|
import regex
|
|
sign = ''
|
|
s = str
|
|
if s and s[0] in '+-':
|
|
sign = s[0]
|
|
s = s[1:]
|
|
if not s:
|
|
raise ValueError, 'non-float argument to string.atof'
|
|
while s[0] == '0' and len(s) > 1 and s[1] in digits: s = s[1:]
|
|
if regex.match('[0-9]*\(\.[0-9]*\)?\([eE][-+]?[0-9]+\)?', s) != len(s):
|
|
raise ValueError, 'non-float argument to string.atof'
|
|
try:
|
|
return float(eval(sign + s))
|
|
except SyntaxError:
|
|
raise ValueError, 'non-float argument to string.atof'
|
|
|
|
# Convert string to integer
|
|
def atoi(str, base=10):
|
|
if base != 10:
|
|
# We only get here if strop doesn't define atoi()
|
|
raise ValueError, "this string.atoi doesn't support base != 10"
|
|
sign = ''
|
|
s = str
|
|
if s and s[0] in '+-':
|
|
sign = s[0]
|
|
s = s[1:]
|
|
if not s:
|
|
raise ValueError, 'non-integer argument to string.atoi'
|
|
while s[0] == '0' and len(s) > 1: s = s[1:]
|
|
for c in s:
|
|
if c not in digits:
|
|
raise ValueError, 'non-integer argument to string.atoi'
|
|
return eval(sign + s)
|
|
|
|
# Convert string to long integer
|
|
def atol(str, base=10):
|
|
if base != 10:
|
|
# We only get here if strop doesn't define atol()
|
|
raise ValueError, "this string.atol doesn't support base != 10"
|
|
sign = ''
|
|
s = str
|
|
if s and s[0] in '+-':
|
|
sign = s[0]
|
|
s = s[1:]
|
|
if not s:
|
|
raise ValueError, 'non-integer argument to string.atol'
|
|
while s[0] == '0' and len(s) > 1: s = s[1:]
|
|
for c in s:
|
|
if c not in digits:
|
|
raise ValueError, 'non-integer argument to string.atol'
|
|
return eval(sign + s + 'L')
|
|
|
|
# Left-justify a string
|
|
def ljust(s, width):
|
|
n = width - len(s)
|
|
if n <= 0: return s
|
|
return s + ' '*n
|
|
|
|
# Right-justify a string
|
|
def rjust(s, width):
|
|
n = width - len(s)
|
|
if n <= 0: return s
|
|
return ' '*n + s
|
|
|
|
# Center a string
|
|
def center(s, width):
|
|
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):
|
|
if type(x) == type(''): s = x
|
|
else: s = `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):
|
|
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):
|
|
if type(table) != type('') or len(table) != 256:
|
|
raise TypeError, "translation table must be 256-char string"
|
|
res = ""
|
|
for c in s:
|
|
res = res + table[ord(c)]
|
|
return res
|
|
|
|
# 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 *
|
|
letters = lowercase + uppercase
|
|
except ImportError:
|
|
pass # Use the original, slow versions
|