def translate(s, a, b=None, c=None):
"""Return ``s`` where characters have been replaced or deleted.
SYNTAX
======
translate(s, None, deletechars):
all characters in ``deletechars`` are deleted
translate(s, map [,deletechars]):
all characters in ``deletechars`` (if provided) are deleted
then the replacements defined by map are made; if the keys
of map are strings then the longer ones are handled first.
Multicharacter deletions should have a value of ''.
translate(s, oldchars, newchars, deletechars)
all characters in ``deletechars`` are deleted
then each character in ``oldchars`` is replaced with the
corresponding character in ``newchars``
Examples
========
>>> from sympy.utilities.misc import translate
>>> from sympy.core.compatibility import unichr
>>> abc = 'abc'
>>> translate(abc, None, 'a')
'bc'
>>> translate(abc, {'a': 'x'}, 'c')
'xb'
>>> translate(abc, {'abc': 'x', 'a': 'y'})
'x'
>>> translate('abcd', 'ac', 'AC', 'd')
'AbC'
There is no guarantee that a unique answer will be
obtained if keys in a mapping overlap are the same
length and have some identical sequences at the
beginning/end:
>>> translate(abc, {'ab': 'x', 'bc': 'y'}) in ('xc', 'ay')
True
"""
from sympy.core.compatibility import maketrans, PY3
mr = {}
if a is None:
assert c is None
if not b:
return s
c = b
a = b = ''
else:
if type(a) is dict:
short = {}
for k in list(a.keys()):
if len(k) == 1 and len(a[k]) == 1:
short[k] = a.pop(k)
mr = a
c = b
if short:
a, b = [''.join(i) for i in list(zip(*short.items()))]
else:
a = b = ''
else:
assert len(a) == len(b)
if PY3:
if c:
s = s.translate(maketrans('', '', c))
s = replace(s, mr)
return s.translate(maketrans(a, b))
else:
# when support for Python 2 is dropped, this if-else-block
# can be replaced with the if-clause
if c:
c = list(c)
rem = {}
for i in range(-1, -1 - len(c), -1):
if ord(c[i]) > 255:
rem[c[i]] = ''
c.pop(i)
s = s.translate(None, ''.join(c))
s = replace(s, rem)
if a:
a = list(a)
b = list(b)
for i in range(-1, -1 - len(a), -1):
if ord(a[i]) > 255 or ord(b[i]) > 255:
mr[a.pop(i)] = b.pop(i)
a = ''.join(a)
b = ''.join(b)
s = replace(s, mr)
table = maketrans(a, b)
# s may have become unicode which uses the py3 syntax for translate
if type(table) is str and type(s) is str:
s = s.translate(table)
else:
s = s.translate(dict(
[(i, ord(c)) for i, c in enumerate(table)]))
return s
def translate(s, a, b=None, c=None):
"""Return ``s`` where characters have been replaced or deleted.
SYNTAX
======
translate(s, None, deletechars):
all characters in ``deletechars`` are deleted
translate(s, map [,deletechars]):
all characters in ``deletechars`` (if provided) are deleted
then the replacements defined by map are made; if the keys
of map are strings then the longer ones are handled first.
Multicharacter deletions should have a value of ''.
translate(s, oldchars, newchars, deletechars)
all characters in ``deletechars`` are deleted
then each character in ``oldchars`` is replaced with the
corresponding character in ``newchars``
Examples
========
>>> from sympy.utilities.misc import translate
>>> from sympy.core.compatibility import unichr
>>> abc = 'abc'
>>> translate(abc, None, 'a')
'bc'
>>> translate(abc, {'a': 'x'}, 'c')
'xb'
>>> translate(abc, {'abc': 'x', 'a': 'y'})
'x'
>>> translate('abcd', 'ac', 'AC', 'd')
'AbC'
There is no guarantee that a unique answer will be
obtained if keys in a mapping overlap are the same
length and have some identical sequences at the
beginning/end:
>>> translate(abc, {'ab': 'x', 'bc': 'y'}) in ('xc', 'ay')
True
"""
from sympy.core.compatibility import maketrans, PY3
mr = {}
if a is None:
if c is not None:
raise ValueError(
'c should be None when a=None is passed, instead got %s' % c)
if b is None:
return s
c = b
a = b = ''
else:
if type(a) is dict:
short = {}
for k in list(a.keys()):
if len(k) == 1 and len(a[k]) == 1:
short[k] = a.pop(k)
mr = a
c = b
if short:
a, b = [''.join(i) for i in list(zip(*short.items()))]
else:
a = b = ''
elif len(a) != len(b):
raise ValueError('oldchars and newchars have different lengths')
if PY3:
if c:
s = s.translate(maketrans('', '', c))
s = replace(s, mr)
return s.translate(maketrans(a, b))
else:
# when support for Python 2 is dropped, this if-else-block
# can be replaced with the if-clause
if c:
c = list(c)
rem = {}
for i in range(-1, -1 - len(c), -1):
if ord(c[i]) > 255:
rem[c[i]] = ''
c.pop(i)
s = s.translate(None, ''.join(c))
s = replace(s, rem)
if a:
a = list(a)
b = list(b)
for i in range(-1, -1 - len(a), -1):
if ord(a[i]) > 255 or ord(b[i]) > 255:
mr[a.pop(i)] = b.pop(i)
a = ''.join(a)
b = ''.join(b)
s = replace(s, mr)
table = maketrans(a, b)
# s may have become unicode which uses the py3 syntax for translate
if isinstance(table, str) and isinstance(s, str):
s = s.translate(table)
else:
s = s.translate(dict([(i, ord(c)) for i, c in enumerate(table)]))
return s
