Sorting a list of string based on digit

Question

I have a list of string

line = ["set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','B10_Stat_TRXA_FCC'),'port', '1218');",
"set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','Az_INS3_RawValidity'),'port', '1438');"]

I am trying to sort is based on last digit 1438 and 1218 sorting numerically ..'1438' should be treated as number

below lines doesn't give me expected result

line = sorted(line)

["set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','Az_INS3_RawValidity'),'port', '1438');",
 "set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','B10_Stat_TRXA_FCC'),'port', '1218');"]

the last digit in both of your examples is `8`, are you trying to sort them alphabetically or numerically? — Sayse, Sep 19 '18 at 20:01
@vash_the_stampede - Comparing how? alphabetically or numerically? What should come first with 107 and 11? — Sayse, Sep 19 '18 at 20:03
@Sayse well his response has them 1408 first and is wrong so if you have 107 and 11, I would say he wants 11 first 107 second — vash_the_stampede, Sep 19 '18 at 20:06

sacuL · Answer 1 · 2018-09-19T20:04:05.923

2

You can use a regex to find the last occurrence of digits surrounded by single quotes in the key argument of sorted:

import re

sorted(line,key=lambda x: int(re.findall("'(\d+)'", x)[-1]))

edited Sep 19 '18 at 20:04

answered Sep 19 '18 at 20:00

sacuL

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score 1 · Accepted Answer · answered Sep 19 '18 at 20:02

You could extract the sub-string from the last comma onwards and then extract the digits from that string.

sorted(line, key=lambda s: int(''.join(c for c in s.split(',')[-1] if c.isdigit())))

giving

["set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','B10_Stat_TRXA_FCC'),'port', '1218');", 
"set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','Az_INS3_RawValidity'),'port', '1438');"]

Alexander · Answer 3 · 2018-09-19T20:15:54.137

1

Assuming your data stays in that format:

>>> sorted(line, key=lambda x: int(x.split()[-1][1:-3]))
["set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','B10_Stat_TRXA_FCC'),'port', '1218');",
 "set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name','Az_INS3_RawValidity'),'port', '1438');"]

I takes each line, splits it, and then takes the last item (e.g. "'1218');" for the first line). It then strips the first character (') and the last three (');) via slice notation. Finally, it converts this text value to an integer and uses it as a key for sorting.

A regex solution is more general.

sorted(line, key=lambda x: int(re.findall(r'(\d+)', x.split()[-1])[0]))

This will fail if the last item in the split does not contain any digits.

edited Sep 19 '18 at 20:15

answered Sep 19 '18 at 20:06

Alexander

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This is what I was going for as well, but we would have to assume it will always be 4 digits correct? – vash_the_stampede Sep 19 '18 at 20:10
Oh you are right, it will always have 3 characters at the end, I was thinking your index was based off the width of the numbers but yes it will always be that index – vash_the_stampede Sep 19 '18 at 20:12
`new = sorted(line, key=lambda x: int((x.split()[-1]).split("'")[1]))` I went similar route forgetting the index will always be `[1:-3]` – vash_the_stampede Sep 19 '18 at 20:14

score 0 · Answer 4 · answered Sep 19 '18 at 20:01

Use python regex (https://docs.python.org/3.6/library/re.html) to extract the integer value at the end of the strings, then you can create a function which takes your string as an argument, and returns the integer.

Finally, used a lambda to the key argument to the sorted method to pass in the function. Python will used your function as the key to sort with. (like this: Syntax behind sorted(key=lambda: ...) )

score 0 · Answer 5 · answered Sep 19 '18 at 20:13

Not as good as @Alexander response, same result but extra step

new = sorted(line, key=lambda x: int((x.split()[-1]).split("'")[1]))

(xenial)vash@localhost:~/python/stack_overflow$ python3.7 list.py

["set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name'
,'B10_Stat_TRXA_FCC'),'port', '1218');", 
"set_param(find_system('Fccroot_to_ICD','RegExp','on','FindAll','on','Name',
'Az_INS3_RawValidity'),'port', '1438');"]

Sorting a list of string based on digit

5 Answers5