Ignoring strings in a list using regular expressions in python [duplicate]

Question

I am fetching some information from the sites and for example i am fetching address of some customers

address = ['Mr Thomas',
 '+(91)-9849633132, 9959455935',
 '+(91)-9849633132',
 '9196358485',
 '8846853128',
 '8-4-236/2']

From the above list i want to ignore strings starting with +(91) and 9 and 8 which are nothing but the phone numbers, so i used regular expressions as below

import re


result = [i for i in address if not re.match(r"[98]\B", i)]

result

['Mr Thomas','+(91)-9849633132, 9959455935','+(91)-9849633132','8-4-236/2']

That is the strings starting with 9 and 8 are ignored but i want to ignore the strings starting with +(91) too , can anyone please let me know how to do this.

Josiah · Accepted Answer · 2012-08-07 10:00:27Z

1

Just add in another check for the +(91), using the | (or) operator. Like so:

>>> [i for i in address if not re.match(r"[98]\B|\+\(91\)\B", i)]
['Mr Thomas', '8-4-236/2']

Note that you have to escape +, (, and ) because those are special characters.

As an aside, it might be more efficient to use a filter, rather than a list comprehension:

>>> filter(lambda x: not re.match(r"[98]\B|\+\(91\)\B", x), address)
['Mr Thomas', '8-4-236/2']

Though I can't be sure.

Edit: Looks like it's not more efficient. However, I find it to be more self documenting, but you can take it as you will.

edited Aug 7, 2012 at 10:00

answered Aug 7, 2012 at 9:31

Josiah

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2 Comments

James Over a year ago

I was just running timeit when you edited - regardless, any performance difference would be implementation-dependent, and this would probably be premature optimisation anyway. If performance was a problem, using re.compile might be a more fruitful optimisation.

Josiah Over a year ago

@James I mostly just meant it as a second option. Thank you for confirming though.

Vinayak Kolagi · Accepted Answer · 2012-08-07 09:27:24Z

0

result = [i for i in address if not re.match(r"\+[98]\B", i)]

answered Aug 7, 2012 at 9:27

Vinayak Kolagi

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2 Comments

Shiva Krishna Bavandla Over a year ago

Thats not working actually and i am getting the same result

Josiah Over a year ago

@shivakrishna That should actually give you a result that doesn't match any of the strings in your list.

user1016274 · Accepted Answer · 2012-08-07 10:28:11Z

0

This does work:

 result = [i for i in s if not re.match(r'[+89][-()+0-9/\s]+',i)]

Why? The '\B' switch is detrimental here as the match MUST NOT occur at the beginning of the string. Additionally, the proposed search pattern allows for white space within the numbers.

answered Aug 7, 2012 at 10:28

user1016274

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