maxsplit question

[tester_V]

Greetings!
I'm confused about the maxsplit.
Here is an example.

s = 'BKM0001-01-XLPM034NMS'
print(f"*** {s} ***")
dd = s.split('-',2)[0]
print(dd)

I'm trying to get 'BKM0001-01' from the string. I thought I'm splitting the string on the second (-) delimiter and it would print only the [0] element of the split, that is 'BKM0001-01' and I wanted to use the 'XLPM034NMS' the element 1 for something else.
But it prints 'BKM0001', no the 'BKM0001-01'

Thank you.

[bowlofred]

split() always splits on the delimters from left to right. What the maxsplit does is tell it when to stop looking for delimiters.

>>> "A-B-C-D".split("-")
['A', 'B', 'C', 'D']
>>> "A-B-C-D".split("-", 2)
['A', 'B', 'C-D']
>>> "A-B-C-D".split("-", 1)
['A', 'B-C-D']
>>> "A-B-C-D".split("-", 0)
['A-B-C-D']

Since you only have 2 delimiters, you could use rsplit() instead which splits right to left.

>>> "BKM0001-01-XLPM034NMS".rsplit("-", 1)[0]
'BKM0001-01'

or if you had a variable number, you could just split the first three, and rejoin the first 2.

>>> "-".join("BKM0001-01-XLPM034NMS".split("-", 2)[:2])
'BKM0001-01'

[tester_V]

Awesome!
Thank you!