[Tutor] Search and replace

[Danny Yoo]

On Wed, 15 Jan 2003, Paul Hartley wrote:

> I have some text that contains semicolons surounded by spaces, for
> example :-
>
> 123 ;345   ;   456; 55 ;    ;   ;123 abc
>
> And I want to remove those spaces, but not other spaces, so the above
> line would be :-
>
> 123;345;456;55;;;123 abc

Hi Paul:

I see, so you want to strip off the whitespace around every field that's
split up by semicolons.


> I know there must be a simple way using re - I have done this but used
> two while loops until all the spaces are gone, not very elegant.

Yes, there's a clean way of doing this.  If we take a look at the split(),
strip(), and join() methods of strings:

    http://www.python.org/doc/lib/string-methods.html

we should see the tools we need to strip() out the whitespace on each
field of our string.  For example:

###
>>> sentence = "this+is+a+test"
>>> sentence.split("+")
['this', 'is', 'a', 'test']
>>> words = sentence.split("+")
>>> new_words = [w.capitalize() for w in words]
>>> new_words
['This', 'Is', 'A', 'Test']
>>> '-'.join(new_words)
'This-Is-A-Test'
###

shows a few ways that the string methods can simplify our string fiddling,
without using loops.  I'll be vague for the moment on how the pieces fit
together exactly for your problem.  *grin*


If you run into problems, please feel free to ask again on Tutor.  Good
luck to you!