How to split a string based on underscore but conditional

Question

I have a string below which altogether joined by underscores _ that i want to split in such a way to get my desired output.

Below is list string:

>>> a
'cDOT_stv3027_esx_vdi01_07-24-2021_02.00.00.0443'

>>> type(a)
<type 'str'>

Simple rsplit() operation by 2 which turns it into 3 different list values as shown below, like from the end its time , date and then one combine strings ie 'cDOT_stv3027_esx_vdi01' which i want to split into two parts like 'cDOT' & 'stv3027_esx_vdi01'.

>>> a.rsplit("_",2)
['cDOT_stv3027_esx_vdi01', '07-24-2021', '02.00.00.0443']

I am trying below on the first index but then i'll not retain rest of values.

>>> a.rsplit("_",2)[0].split("_",1)
['cDOT', 'stv3027_esx_vdi01']

My desired output should be like below:

['cDOT', 'stv3027_esx_vdi01', '07-24-2021', '02.00.00.0443']

It seems to me that you already have all you need just by joining your 2 (sub)lists: `a.rsplit("_",2)[0].split("_",1) + a.rsplit("_",2)[1:]` — Demi-Lune, Jul 27 '21 at 15:18

score 4 · Accepted Answer · answered Jul 27 '21 at 15:26

4

You can use

a = 'cDOT_stv3027_esx_vdi01_07-24-2021_02.00.00.0443'
prefix, *mid, date, time = a.split('_')
print(prefix, '_'.join(mid), date, time)

See the online Python demo.

In this case, you can have as many underscore separated parts between the prefix and date as there are.

answered Jul 27 '21 at 15:26

Wiktor Stribiżew

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Thanks WiKtor for the diffrent approach +1 already, by the way what is `*mid` specially `*` , if you little explain. – user2023 Jul 28 '21 at 08:37
@kulfi "Splat", or "unpacking" operator, see [more here](https://stackoverflow.com/a/2322384/3832970). – Wiktor Stribiżew Jul 28 '21 at 09:04

score 2 · Answer 2 · answered Jul 27 '21 at 15:21

Assuming you will always want the joined substrings to be the same:

splits = a.split('_')
[splits[0]] + ['_'.join(splits[1:4])] + splits[4:]

>>> [splits[0]] + ['_'.join(splits[1:4])] + splits[4:]
['cDOT', 'stv3027_esx_vdi01', '07-24-2021', '02.00.00.0443']

score 1 · Answer 3 · answered Jul 27 '21 at 15:20

It seems to me that you don't really want to split the data, you want to extract the relevant parts. For that, I'd recommend using regex.

import re

m = re.match(r"^(.*)_(.*_.*_.*)_(.*)_(.*)$", a)

# Your results:
[m.group(1), m.group(2), m.group(3), m.group(4)]

This way you are capturing everything until the first underscore in group 1, the next three underscore separated sections into group 2, the date in group 3 and the final part to group 4.

Thus the result will look like this:

['cDOT', 'stv3027_esx_vdi01', '07-24-2021', '02.00.00.0443']

score 1 · Answer 4 · answered Jul 27 '21 at 15:26

Why not just do it in two steps ?

string = 'cDOT_stv3027_esx_vdi01_07-24-2021_02.00.00.0443'

splited_line = string.rsplit('_', 2)
print(splited_line[0].split('_', 1) + splited_line[1:])

output :

['cDOT', 'stv3027_esx_vdi01', '07-24-2021', '02.00.00.0443']

score 1 · Answer 5 · answered Jul 27 '21 at 15:27

Using regex:

>>> re.findall('(.*?)_(.*?)_(\d+.*?)_(.*)', a)[0]
('cDOT', 'stv3027_esx_vdi01', '07-24-2021', '02.00.00.0443')

Understanding the pattern:

(.*?)_(.*?)_(\d+.*?)_(.*)

(.*?)_ : It will match the substring before first underscore

(.*?)_(\d+.*?)_ : It will match the substring until underscore followed by 
                  at least one digits, but will get you one substring before underscore, 
                  and one sebstring after underscore and before the next underscore 
                  encountered

(.*) : It will get the remaining part of the string.

score 1 · Answer 6 · answered Jul 27 '21 at 15:46

1

In one line using split(), rsplit() and partition():

a.split('_')[:1] + a.partition('_')[2].rsplit('_', 2)

answered Jul 27 '21 at 15:46

ettanany

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How to split a string based on underscore but conditional

6 Answers6