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# Copyright 2000 by Jeffrey Chang. All rights reserved.
# This code is part of the Biopython distribution and governed by its
# license. Please see the LICENSE file that should have been included
# as part of this package.
"""This provides useful general functions for working with strings.
Functions:
splitany Split a string using many delimiters.
find_anychar Find one of a list of characters in a string.
rfind_anychar Find one of a list of characters in a string, from end to start.
starts_with Check whether a string starts with another string.
"""
def splitany(s, sep=" \011\012\013\014\015", maxsplit=None, negate=0):
"""splitany(s [,sep [,maxsplit [,negate]]]) -> list of strings
Split a string. Similar to string.split, except that this considers
any one of the characters in sep to be a delimiter. If negate is
true, then everything but sep will be a separator.
"""
strlist = []
prev = 0
for i in range(len(s)):
if maxsplit is not None and len(strlist) >= maxsplit:
break
if (s[i] in sep) == (not negate):
strlist.append(s[prev:i])
prev = i+1
strlist.append(s[prev:])
return strlist
def find_anychar(string, chars, index=None, negate=0):
"""find_anychar(string, chars[, index]) -> index of a character or -1
Find a character in string. chars is a list of characters to look
for. Return the index of the first occurrence of any of the
characters, or -1 if not found. index is the index where the
search should start. By default, I search from the beginning of
the string.
"""
if index is None:
index = 0
while index < len(string) and \
((not negate and string[index] not in chars) or
(negate and string[index] in chars)):
index += 1
if index == len(string):
return -1
return index
def rfind_anychar(string, chars, index=None, negate=0):
"""rfind_anychar(string, chars[, index]) -> index of a character or -1
Find a character in string, looking from the end to the start.
chars is a list of characters to look for. Return the index of
the first occurrence of any of the characters, or -1 if not found.
index is the index where the search should start. By default, I
search from the end of the string.
"""
if index is None:
index = len(string)-1
while index >= 0 and \
((not negate and string[index] not in chars) or
(negate and string[index] in chars)):
index -= 1
# If not found, index will already be -1.
return index
# XXX should deprecate. Python 2.0 and above has ''.startswith function.
def starts_with(s, start):
"""starts_with(s, start) -> 1/0
Return whether s begins with start.
"""
return s[:len(start)] == start
# Try and load C implementations of functions. If I can't,
# then just ignore and use the pure python implementations.
try:
from cstringfns import *
except ImportError:
pass
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