Checking and removing extra symbols

Question

I'm interested by removing extra symbols from strings in python.

What could by the more efficient and pythonic way to do that ? Is there some grammar module ?

My first idea would be to locate the more nested text and go through the left and the right, counting the opening and closing symbols. Then i remove the last one of the symbol counter that contain too much symbol.

An example would be this string

text = "(This (is an example)"

You can clearly see that the first parenthesis is not balanced by another one. So i want to delete it.

text = "This (is and example)"

The solution has to be independant of the position of the parentheses.

Others example could be :

text = "(This (is another example) )) (to) explain) the question"

That would become :

text = "(This (is another example) ) (to) explain the question"

Maybe checkout the [string docs](http://docs.python.org/2/library/stdtypes.html#string-methods) — danodonovan, Jan 10 '13 at 17:30
Ashwini Chaudhary is right, we need more info. But, from the info given, my first thought would be regular expressions. Look at re.sub(...). — Jamie Duby, Jan 10 '13 at 17:55
Given the example, I think this has already been answered. http://stackoverflow.com/questions/5454322/python-how-to-match-nested-parentheses-with-regex — Jamie Duby, Jan 10 '13 at 18:39

score 0 · Answer 1 · edited Jan 10 '13 at 18:33

Had to break this into an answer for formatting. Check the Python's regular expression module.

If I'm understanding what you are asking, look at re.sub. You can use a regular expression to find the character you'd like to remove, and replace them with an empty string.

Suppose we want to remove all instances of '.', '&', and '*'.

>>> import re
>>> s = "abc&def.ghi**jkl&"
>>> re.sub('[\.\&\*]', '', s)
'abcdefghijkl'

If the pattern to be matched is larger, you can use re.compile and pass that as the first argument to sub.

>>> r = re.compile('[\.\&\*]')
>>> re.sub(r, '', s)
'abcdefghijkl'

Hope this helps.

Checking and removing extra symbols

1 Answers1