CODEWITHSUNDEEP
python
MyNameIsKhan
MyNameIsKhan

Reputation: 2612

How to apply a mask to a number or string in Python?

I don't know if masks can only be applied to strings or numbers so I included both in my title (since I can always translate between the two later).

Let's say I have a mask mask = '001001' and I want to somehow say "for all positions in the mask that equal 1, apply X to those same positions in this other string".

For instance say I have a number 123456 and I apply that mask to it and want to set the digits to 0. I'd get 120450.

Apologies if I am not making sense. Please suggest an ideal mask type if my earlier string example is not the best, and an easy way to use it to apply changes to a separate number/string.

Upvotes: 2

Views: 7549

Answers (1)

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 251051

In [272]: mask = '001001'

In [273]: num=123456

In [274]: "".join(x if y!='1' else '0' for x,y in zip(str(num),mask))
Out[274]: '120450'

use itertools.izip_longest() if the number and the mask string are of different length:

In [277]: mask = '001001'

In [278]: num=12345678

In [279]: "".join(x if y!='1' else '0' for x,y in izip_longest(str(num),mask,fillvalue="#"))
Out[279]: '12045078'

Upvotes: 7

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