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Added doc string, provided by Charles Waldman (with some reformatting 

and a little editing my me).
This commit is contained in:
Guido van Rossum 1997-12-29 19:26:28 +00:00
parent 6884e3b94b
commit 2003204ba7
2 changed files with 446 additions and 0 deletions
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223
Lib/string.py
View File

@ -4,6 +4,20 @@
# At the end of this file most functions are replaced by built-in
# functions imported from built-in module "strop".
"""Common string manipulations.
Public module variables:
whitespace -- a string containing all characters considered whitespace
lowercase -- a string containing all characters considered lowercase letters
uppercase -- a string containing all characters considered uppercase letters
letters -- a string containing all characters considered letters
digits -- a string containing all characters considered decimal digits
hexdigits -- a string containing all characters considered hexadecimal digits
octdigits -- a string containing all characters considered octal digits
"""
# Some strings for ctype-style character classification
whitespace = ' \t\n\r\v\f'
lowercase = 'abcdefghijklmnopqrstuvwxyz'
@ -29,6 +43,11 @@ atol_error = ValueError
# convert UPPER CASE letters to lower case
def lower(s):
"""lower(s) -> string
Return a copy of the string s converted to lowercase
"""
res = ''
for c in s:
res = res + _lower[ord(c)]
@ -36,6 +55,11 @@ def lower(s):
# Convert lower case letters to UPPER CASE
def upper(s):
"""upper(s) -> string
Return a copy of the string s converted to uppercase
"""
res = ''
for c in s:
res = res + _upper[ord(c)]
@ -43,6 +67,12 @@ def upper(s):
# Swap lower case letters and UPPER CASE
def swapcase(s):
"""swapcase(s) -> strng
Return a copy of the string s with upper case characters
converted to lowercase and vice versa
"""
res = ''
for c in s:
res = res + _swapcase[ord(c)]
@ -50,6 +80,12 @@ def swapcase(s):
# Strip leading and trailing tabs and spaces
def strip(s):
"""strip(s) -> string
Return a copy of the string s with leading and trailing
whitespace removed
"""
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
@ -57,12 +93,22 @@ def strip(s):
# Strip leading tabs and spaces
def lstrip(s):
"""lstrip(s) -> string
Return a copy of the string s with leading whitespace removed
"""
i, j = 0, len(s)
while i < j and s[i] in whitespace: i = i+1
return s[i:j]
# Strip trailing tabs and spaces
def rstrip(s):
"""rstrip(s) -> string
Return a copy of the string s with trailing whitespace removed
"""
i, j = 0, len(s)
while i < j and s[j-1] in whitespace: j = j-1
return s[i:j]
@ -71,6 +117,16 @@ def rstrip(s):
# 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, maxsplit=0):
"""split(str [,sep [,maxsplit]]) -> list of strings
Return a list of the words in the string s, using sep as the
delimiter string. If maxsplit is nonzero, splits into at most
maxsplit words If sep is not specified, any whitespace string
is a separator. Maxsplit defaults to 0.
(split and splitfields are synonymous)
"""
if sep is not None: return splitfields(s, sep, maxsplit)
res = []
i, n = 0, len(s)
@ -93,6 +149,16 @@ def split(s, sep=None, maxsplit=0):
# 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, maxsplit=0):
"""splitfields(str [,sep [,maxsplit]]) -> list of strings
Return a list of the words in the string s, using sep as the
delimiter string. If maxsplit is nonzero, splits into at most
maxsplit words If sep is not specified, any whitespace string
is a separator. Maxsplit defaults to 0.
(split and splitfields are synonymous)
"""
if sep is None: return split(s, None, maxsplit)
res = []
nsep = len(sep)
@ -116,10 +182,28 @@ def splitfields(s, sep=None, maxsplit=0):
# Join words with spaces between them
def join(words, sep = ' '):
"""join(list [,sep]) -> string
Return a string composed of the words in list, with
intervening occurences of sep. The default separator is a
single space.
(joinfields and join are synonymous)
"""
return joinfields(words, sep)
# Join fields with optional separator
def joinfields(words, sep = ' '):
"""joinfields(list [,sep]) -> string
Return a string composed of the words in list, with
intervening occurences of sep. The default separator is a
single space.
(joinfields and join are synonymous)
"""
res = ''
for w in words:
res = res + (sep + w)
@ -127,6 +211,15 @@ def joinfields(words, sep = ' '):
# Find substring, raise exception if not found
def index(s, sub, i = 0, last=None):
"""index(s, sub [,start [,end]]) -> int
Return the lowest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Raise ValueError if not found.
"""
if last is None: last = len(s)
res = find(s, sub, i, last)
if res < 0:
@ -135,6 +228,15 @@ def index(s, sub, i = 0, last=None):
# Find last substring, raise exception if not found
def rindex(s, sub, i = 0, last=None):
"""rindex(s, sub [,start [,end]]) -> int
Return the highest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Raise ValueError if not found.
"""
if last is None: last = len(s)
res = rfind(s, sub, i, last)
if res < 0:
@ -143,6 +245,13 @@ def rindex(s, sub, i = 0, last=None):
# Count non-overlapping occurrences of substring
def count(s, sub, i = 0, last=None):
"""count(s, sub[, start[,end]]) -> int
Return the number of occurrences of substring sub in string
s[start:end]. Optional arguments start and end are
interpreted as in slice notation.
"""
Slen = len(s) # cache this value, for speed
if last is None:
last = Slen
@ -165,6 +274,15 @@ def count(s, sub, i = 0, last=None):
# Find substring, return -1 if not found
def find(s, sub, i = 0, last=None):
"""find(s, sub [,start [,end]]) -> in
Return the lowest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Return -1 on failure.
"""
Slen = len(s) # cache this value, for speed
if last is None:
last = Slen
@ -182,6 +300,15 @@ def find(s, sub, i = 0, last=None):
# Find last substring, return -1 if not found
def rfind(s, sub, i = 0, last=None):
"""rfind(s, sub [,start [,end]]) -> int
Return the highest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Returns -1 on failure.
"""
Slen = len(s) # cache this value, for speed
if last is None:
last = Slen
@ -204,6 +331,11 @@ safe_env = {"__builtins__": {}}
# Convert string to float
re = None
def atof(str):
"""atof(s) -> float
Return the floating point number represented by the string s.
"""
global re
if re is None:
# Don't fail if re doesn't exist -- just skip the syntax check
@ -228,6 +360,16 @@ def atof(str):
# Convert string to integer
def atoi(str, base=10):
"""atoi(s [,base]) -> int
Return the integer represented by the string s in the given
base, which defaults to 10. The string s must consist of one
or more digits, possibly preceded by a sign. If base is 0, it
is chosen from the leading characters of s, 0 for octal, 0x or
0X for hexadecimal. If base is 16, a preceding 0x or 0X is
accepted.
"""
if base != 10:
# We only get here if strop doesn't define atoi()
raise ValueError, "this string.atoi doesn't support base != 10"
@ -246,6 +388,17 @@ def atoi(str, base=10):
# Convert string to long integer
def atol(str, base=10):
"""atol(s [,base]) -> long
Return the long integer represented by the string s in the
given base, which defaults to 10. The string s must consist
of one or more digits, possibly preceded by a sign. If base
is 0, it is chosen from the leading characters of s, 0 for
octal, 0x or 0X for hexadecimal. If base is 16, a preceding
0x or 0X is accepted. A trailing L or l is not accepted,
unless base is 0.
"""
if base != 10:
# We only get here if strop doesn't define atol()
raise ValueError, "this string.atol doesn't support base != 10"
@ -264,18 +417,39 @@ def atol(str, base=10):
# Left-justify a string
def ljust(s, width):
"""ljust(s, width) -> string
Return a left-justified version of s, in a field of the
specified width, padded with spaces as needed. The string is
never truncated.
"""
n = width - len(s)
if n <= 0: return s
return s + ' '*n
# Right-justify a string
def rjust(s, width):
"""rjust(s, width) -> string
Return a right-justified version of s, in a field of the
specified width, padded with spaces as needed. The string is
never truncated.
"""
n = width - len(s)
if n <= 0: return s
return ' '*n + s
# Center a string
def center(s, width):
"""center(s, width) -> string
Return a center version of s, in a field of the specified
width. padded with spaces as needed. The string is never
truncated.
"""
n = width - len(s)
if n <= 0: return s
half = n/2
@ -288,6 +462,12 @@ def center(s, width):
# 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):
"""zfill(x, width) -> string
Pad a numeric string x with zeros on the left, to fill a field
of the specified width. The string x is never truncated.
"""
if type(x) == type(''): s = x
else: s = `x`
n = len(s)
@ -300,6 +480,13 @@ def zfill(x, width):
# Expand tabs in a string.
# Doesn't take non-printing chars into account, but does understand \n.
def expandtabs(s, tabsize=8):
"""expandtabs(s [,tabsize]) -> string
Return a copy of the string s with all tab characters replaced
by the appropriate number of spaces, depending on the current
column, and the tabsize (default=8).
"""
res = line = ''
for c in s:
if c == '\t':
@ -312,6 +499,14 @@ def expandtabs(s, tabsize=8):
# Character translation through look-up table.
def translate(s, table, deletions=""):
"""translate(s,table [,deletechars]) -> string
Return a copy of the string s, where all characters occurring
in the optional argument deletechars are removed, and the
remaining characters have been mapped through the given
translation table, which must be a string of length 256.
"""
if type(table) != type('') or len(table) != 256:
raise TypeError, "translation table must be 256 characters long"
res = ""
@ -322,16 +517,37 @@ def translate(s, table, deletions=""):
# Capitalize a string, e.g. "aBc dEf" -> "Abc def".
def capitalize(s):
"""capitalize(s) -> string
Return a copy of the string s with only its first character
capitalized.
"""
return upper(s[:1]) + lower(s[1:])
# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
# See also regsub.capwords().
def capwords(s, sep=None):
"""capwords(s, [sep]) -> string
Split the argument into words using split, capitalize each
word using capitalize, and join the capitalized words using
join. Note that this replaces runs of whitespace characters by
a single space.
"""
return join(map(capitalize, split(s, sep)), sep or ' ')
# Construct a translation string
_idmapL = None
def maketrans(fromstr, tostr):
"""maketrans(frm, to) -> string
Return a translation table (a string of 256 bytes long)
suitable for use in string.translate. The strings frm and to
must be of the same length.
"""
if len(fromstr) != len(tostr):
raise ValueError, "maketrans arguments must have same length"
global _idmapL
@ -345,6 +561,13 @@ def maketrans(fromstr, tostr):
# Substring replacement (global)
def replace(str, old, new, maxsplit=0):
"""replace (str, old, new[, maxsplit]) -> string
Return a copy of string str with all occurrences of substring
old replaced by new. If the optional argument maxsplit is
given, only the first maxsplit occurrences are replaced.
"""
return joinfields(splitfields(str, old, maxsplit), new)

223
Lib/stringold.py
View File

@ -4,6 +4,20 @@
# At the end of this file most functions are replaced by built-in
# functions imported from built-in module "strop".
"""Common string manipulations.
Public module variables:
whitespace -- a string containing all characters considered whitespace
lowercase -- a string containing all characters considered lowercase letters
uppercase -- a string containing all characters considered uppercase letters
letters -- a string containing all characters considered letters
digits -- a string containing all characters considered decimal digits
hexdigits -- a string containing all characters considered hexadecimal digits
octdigits -- a string containing all characters considered octal digits
"""
# Some strings for ctype-style character classification
whitespace = ' \t\n\r\v\f'
lowercase = 'abcdefghijklmnopqrstuvwxyz'
@ -29,6 +43,11 @@ atol_error = ValueError
# convert UPPER CASE letters to lower case
def lower(s):
"""lower(s) -> string
Return a copy of the string s converted to lowercase
"""
res = ''
for c in s:
res = res + _lower[ord(c)]
@ -36,6 +55,11 @@ def lower(s):
# Convert lower case letters to UPPER CASE
def upper(s):
"""upper(s) -> string
Return a copy of the string s converted to uppercase
"""
res = ''
for c in s:
res = res + _upper[ord(c)]
@ -43,6 +67,12 @@ def upper(s):
# Swap lower case letters and UPPER CASE
def swapcase(s):
"""swapcase(s) -> strng
Return a copy of the string s with upper case characters
converted to lowercase and vice versa
"""
res = ''
for c in s:
res = res + _swapcase[ord(c)]
@ -50,6 +80,12 @@ def swapcase(s):
# Strip leading and trailing tabs and spaces
def strip(s):
"""strip(s) -> string
Return a copy of the string s with leading and trailing
whitespace removed
"""
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
@ -57,12 +93,22 @@ def strip(s):
# Strip leading tabs and spaces
def lstrip(s):
"""lstrip(s) -> string
Return a copy of the string s with leading whitespace removed
"""
i, j = 0, len(s)
while i < j and s[i] in whitespace: i = i+1
return s[i:j]
# Strip trailing tabs and spaces
def rstrip(s):
"""rstrip(s) -> string
Return a copy of the string s with trailing whitespace removed
"""
i, j = 0, len(s)
while i < j and s[j-1] in whitespace: j = j-1
return s[i:j]
@ -71,6 +117,16 @@ def rstrip(s):
# 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, maxsplit=0):
"""split(str [,sep [,maxsplit]]) -> list of strings
Return a list of the words in the string s, using sep as the
delimiter string. If maxsplit is nonzero, splits into at most
maxsplit words If sep is not specified, any whitespace string
is a separator. Maxsplit defaults to 0.
(split and splitfields are synonymous)
"""
if sep is not None: return splitfields(s, sep, maxsplit)
res = []
i, n = 0, len(s)
@ -93,6 +149,16 @@ def split(s, sep=None, maxsplit=0):
# 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, maxsplit=0):
"""splitfields(str [,sep [,maxsplit]]) -> list of strings
Return a list of the words in the string s, using sep as the
delimiter string. If maxsplit is nonzero, splits into at most
maxsplit words If sep is not specified, any whitespace string
is a separator. Maxsplit defaults to 0.
(split and splitfields are synonymous)
"""
if sep is None: return split(s, None, maxsplit)
res = []
nsep = len(sep)
@ -116,10 +182,28 @@ def splitfields(s, sep=None, maxsplit=0):
# Join words with spaces between them
def join(words, sep = ' '):
"""join(list [,sep]) -> string
Return a string composed of the words in list, with
intervening occurences of sep. The default separator is a
single space.
(joinfields and join are synonymous)
"""
return joinfields(words, sep)
# Join fields with optional separator
def joinfields(words, sep = ' '):
"""joinfields(list [,sep]) -> string
Return a string composed of the words in list, with
intervening occurences of sep. The default separator is a
single space.
(joinfields and join are synonymous)
"""
res = ''
for w in words:
res = res + (sep + w)
@ -127,6 +211,15 @@ def joinfields(words, sep = ' '):
# Find substring, raise exception if not found
def index(s, sub, i = 0, last=None):
"""index(s, sub [,start [,end]]) -> int
Return the lowest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Raise ValueError if not found.
"""
if last is None: last = len(s)
res = find(s, sub, i, last)
if res < 0:
@ -135,6 +228,15 @@ def index(s, sub, i = 0, last=None):
# Find last substring, raise exception if not found
def rindex(s, sub, i = 0, last=None):
"""rindex(s, sub [,start [,end]]) -> int
Return the highest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Raise ValueError if not found.
"""
if last is None: last = len(s)
res = rfind(s, sub, i, last)
if res < 0:
@ -143,6 +245,13 @@ def rindex(s, sub, i = 0, last=None):
# Count non-overlapping occurrences of substring
def count(s, sub, i = 0, last=None):
"""count(s, sub[, start[,end]]) -> int
Return the number of occurrences of substring sub in string
s[start:end]. Optional arguments start and end are
interpreted as in slice notation.
"""
Slen = len(s) # cache this value, for speed
if last is None:
last = Slen
@ -165,6 +274,15 @@ def count(s, sub, i = 0, last=None):
# Find substring, return -1 if not found
def find(s, sub, i = 0, last=None):
"""find(s, sub [,start [,end]]) -> in
Return the lowest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Return -1 on failure.
"""
Slen = len(s) # cache this value, for speed
if last is None:
last = Slen
@ -182,6 +300,15 @@ def find(s, sub, i = 0, last=None):
# Find last substring, return -1 if not found
def rfind(s, sub, i = 0, last=None):
"""rfind(s, sub [,start [,end]]) -> int
Return the highest index in s where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Returns -1 on failure.
"""
Slen = len(s) # cache this value, for speed
if last is None:
last = Slen
@ -204,6 +331,11 @@ safe_env = {"__builtins__": {}}
# Convert string to float
re = None
def atof(str):
"""atof(s) -> float
Return the floating point number represented by the string s.
"""
global re
if re is None:
# Don't fail if re doesn't exist -- just skip the syntax check
@ -228,6 +360,16 @@ def atof(str):
# Convert string to integer
def atoi(str, base=10):
"""atoi(s [,base]) -> int
Return the integer represented by the string s in the given
base, which defaults to 10. The string s must consist of one
or more digits, possibly preceded by a sign. If base is 0, it
is chosen from the leading characters of s, 0 for octal, 0x or
0X for hexadecimal. If base is 16, a preceding 0x or 0X is
accepted.
"""
if base != 10:
# We only get here if strop doesn't define atoi()
raise ValueError, "this string.atoi doesn't support base != 10"
@ -246,6 +388,17 @@ def atoi(str, base=10):
# Convert string to long integer
def atol(str, base=10):
"""atol(s [,base]) -> long
Return the long integer represented by the string s in the
given base, which defaults to 10. The string s must consist
of one or more digits, possibly preceded by a sign. If base
is 0, it is chosen from the leading characters of s, 0 for
octal, 0x or 0X for hexadecimal. If base is 16, a preceding
0x or 0X is accepted. A trailing L or l is not accepted,
unless base is 0.
"""
if base != 10:
# We only get here if strop doesn't define atol()
raise ValueError, "this string.atol doesn't support base != 10"
@ -264,18 +417,39 @@ def atol(str, base=10):
# Left-justify a string
def ljust(s, width):
"""ljust(s, width) -> string
Return a left-justified version of s, in a field of the
specified width, padded with spaces as needed. The string is
never truncated.
"""
n = width - len(s)
if n <= 0: return s
return s + ' '*n
# Right-justify a string
def rjust(s, width):
"""rjust(s, width) -> string
Return a right-justified version of s, in a field of the
specified width, padded with spaces as needed. The string is
never truncated.
"""
n = width - len(s)
if n <= 0: return s
return ' '*n + s
# Center a string
def center(s, width):
"""center(s, width) -> string
Return a center version of s, in a field of the specified
width. padded with spaces as needed. The string is never
truncated.
"""
n = width - len(s)
if n <= 0: return s
half = n/2
@ -288,6 +462,12 @@ def center(s, width):
# 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):
"""zfill(x, width) -> string
Pad a numeric string x with zeros on the left, to fill a field
of the specified width. The string x is never truncated.
"""
if type(x) == type(''): s = x
else: s = `x`
n = len(s)
@ -300,6 +480,13 @@ def zfill(x, width):
# Expand tabs in a string.
# Doesn't take non-printing chars into account, but does understand \n.
def expandtabs(s, tabsize=8):
"""expandtabs(s [,tabsize]) -> string
Return a copy of the string s with all tab characters replaced
by the appropriate number of spaces, depending on the current
column, and the tabsize (default=8).
"""
res = line = ''
for c in s:
if c == '\t':
@ -312,6 +499,14 @@ def expandtabs(s, tabsize=8):
# Character translation through look-up table.
def translate(s, table, deletions=""):
"""translate(s,table [,deletechars]) -> string
Return a copy of the string s, where all characters occurring
in the optional argument deletechars are removed, and the
remaining characters have been mapped through the given
translation table, which must be a string of length 256.
"""
if type(table) != type('') or len(table) != 256:
raise TypeError, "translation table must be 256 characters long"
res = ""
@ -322,16 +517,37 @@ def translate(s, table, deletions=""):
# Capitalize a string, e.g. "aBc dEf" -> "Abc def".
def capitalize(s):
"""capitalize(s) -> string
Return a copy of the string s with only its first character
capitalized.
"""
return upper(s[:1]) + lower(s[1:])
# Capitalize the words in a string, e.g. " aBc dEf " -> "Abc Def".
# See also regsub.capwords().
def capwords(s, sep=None):
"""capwords(s, [sep]) -> string
Split the argument into words using split, capitalize each
word using capitalize, and join the capitalized words using
join. Note that this replaces runs of whitespace characters by
a single space.
"""
return join(map(capitalize, split(s, sep)), sep or ' ')
# Construct a translation string
_idmapL = None
def maketrans(fromstr, tostr):
"""maketrans(frm, to) -> string
Return a translation table (a string of 256 bytes long)
suitable for use in string.translate. The strings frm and to
must be of the same length.
"""
if len(fromstr) != len(tostr):
raise ValueError, "maketrans arguments must have same length"
global _idmapL
@ -345,6 +561,13 @@ def maketrans(fromstr, tostr):
# Substring replacement (global)
def replace(str, old, new, maxsplit=0):
"""replace (str, old, new[, maxsplit]) -> string
Return a copy of string str with all occurrences of substring
old replaced by new. If the optional argument maxsplit is
given, only the first maxsplit occurrences are replaced.
"""
return joinfields(splitfields(str, old, maxsplit), new)