Delete a element using regex from list in python

Question

I have a list in python

a=['one_foo','two_foo','bar_foo']

Expected output:

['one','two','bar']

I tried doing by first converting list into string and then using regex

import re
re.sub("_.*$","", str(a))

I know converting list to string is incorrect way to achieve this task,may be is there any elegant way without converting it to string?

Are you tied to regex or are you willing to consider other solutions? — jpp, Oct 10 '18 at 10:47
What do you want to do with a string like `"test_foo_bar"`? Should the result be `"test_foo"` or `"test"` ? — PM 2Ring, Oct 10 '18 at 10:50
@PM2Ring In that case the result should be "test_foo" (or just remove last string containing '_') — Andre_k, Oct 10 '18 at 10:54

score 2 · Accepted Answer · answered Oct 10 '18 at 10:48

2

You can use a list comprehension with str.rsplit:

a = ['one_foo', 'two_foo', 'bar_foo']

res = [x.rsplit('_', 1)[0] for x in a]

['one', 'two', 'bar']

In general, regex solutions tend to underperform str methods for similar operations.

answered Oct 10 '18 at 10:48

jpp

Perfect solution!, but how `rsplit` is different with 'split' – Andre_k Oct 10 '18 at 10:56
2

`split` works from the left. `rsplit` works from the right. The `1` argument means we only perform one split. – jpp Oct 10 '18 at 10:57

1 Answers1