In the Fish shell, how can I join an array with a custom separator?

Question

I have an array whose elements may contain spaces:

set ASD "a" "b c" "d"

How can I convert this array to a single string of comma-separated values?

# what I want:
"a,b c,d"

So far the closest I could get was converting the array to a string and then replacing all the spaces. The problem is that this only works if the array elements don't contain spaces themselves

(echo $ARR | tr ' ' ',')

score 13 · Accepted Answer · edited Jun 22 '20 at 00:48

13

Since fish 2.3.0 you can use the string builtin:

string join ',' $ASD

The rest of this answer applies to older versions of fish.

One option is to use variable catenation:

echo -s ,$ASD

This adds an extra comma to the beginning. If you want to remove it, you can use cut:

echo -s ,$ASD | cut -b 2-

For completeness, you can also put it after and use sed:

echo -s $ASD, | sed 's/,$//'

edited Jun 22 '20 at 00:48

hugomg

5,747
4
39
54

answered May 24 '15 at 05:00

ridiculous_fish

1,711

Those cut/sed approaches only work if the elements of the array don't contain newline characters. tail -c +2 would be more appropriate. – Stéphane Chazelas Feb 05 '18 at 15:29

cuonglm · Answer 2 · 2015-05-24T03:49:38.423

2

You can use printf and paste instead of echo and tr:

printf '%s\n' $ASD | paste -sd,

AFAIK, fish has no builtin way for joining array elements.

edited May 24 '15 at 03:49

answered May 24 '15 at 03:41

cuonglm

153,898

1

not sure if it was added in the interim or before but the command to join array elements is string join [(-q | --quiet)] SEP [STRING...] - example: string join \n $PATH – tbjgolden Dec 12 '20 at 23:30

In the Fish shell, how can I join an array with a custom separator?

2 Answers2