When using re.sub() part of re for python, a function can be used for sub if I am not mistaken. To my knowledge it passes in the match to whatever function is passed for example:
r = re.compile(r'([A-Za-z]')
r.sub(function,string)
Is there a smarter way to have it pass in a second arg other than with a lambda that calls a method?
r.sub(lambda x: function(x,arg),string)
You can use functools.partial:
>>> from functools import partial
>>> def foo(x, y):
... print x+y
...
>>> partial(foo, y=3)
<functools.partial object at 0xb7209f54>
>>> f = partial(foo, y=3)
>>> f(2)
5
In your example:
def function(x, y):
pass # ...
r.sub(functools.partial(function, y=arg),string)
And a real use with regexes:
>>> s = "the quick brown fox jumps over the lazy dog"
>>> def capitalize_long(match, length):
... word = match.group(0)
... return word.capitalize() if len(word) > length else word
...
>>> r = re.compile('\w+')
>>> r.sub(partial(capitalize_long, length=3), s)
'the Quick Brown fox Jumps Over the Lazy dog'
Without using partials:
import re
a = 'the quick brown fox jumped over the green lazy python'
print re.sub("(\w+)",
lambda x: x.group(1).capitalize(),
a)
Lambda's in Python provide nicely for inline modification of groups.
Having come from Perl, this is how I think of it:
$a = 'the quick brown fox jumped over the green lazy python';
$a =~ s/(\w)(\w+)/uc($1).$2/ge;
print "$a\n";
