python - Split text after the second occurrence of character

Question

I need to split text before the second occurrence of the '-' character. What I have now is producing inconsistent results. I've tried various combinations of rsplit and read through and tried other solutions on SO, with no results.

Sample file name to split: 'some-sample-filename-to-split' returned in data.filename. In this case, I would only like to have 'some-sample' returned.

fname, extname = os.path.splitext(data.filename)
file_label = fname.rsplit('/',1)[-1]
file_label2 = file_label.rsplit('-',maxsplit=3)
print(file_label2,'
','---------------','
')

Answer 1

You can do something like this:

>>> a = "some-sample-filename-to-split"
>>> "-".join(a.split("-", 2)[:2])
'some-sample'

a.split("-", 2) will split the string upto the second occurrence of -.

a.split("-", 2)[:2] will give the first 2 elements in the list. Then simply join the first 2 elements.

OR

You could use regular expression : ^([w]+-[w]+)

>>> import re
>>> reg = r'^([w]+-[w]+)'
>>> re.match(reg, a).group()
'some-sample'

EDIT: As discussed in the comments, here is what you need:

def hyphen_split(a):
    if a.count("-") == 1:
        return a.split("-")[0]
    return "-".join(a.split("-", 2)[:2])

>>> hyphen_split("some-sample-filename-to-split")
'some-sample'
>>> hyphen_split("some-sample")
'some'