Bash pairwise array expansion

Question

I have two arrays of same lengths like following:

arr1[1]=2
arr1[2]=5

arr2[1]=x
arr2[2]=y

I am trying to create a string like "2 x 5 y".

Since the length of the arrays can be a variable, is there any way to do this without using a loop and string concatenation (like parameter expansion or something) ?

That's what I meant. I can use loops. But I want to know if there are any other tricks like expansion to avoid loops. Sorry for the misunderstanding. — Rakib
– Rakib, Commented Dec 29, 2014 at 6:07

anubhava · Accepted Answer · 2014-12-29 06:07:50Z

1

You can use paste with process substitution:

arr1[1]=2
arr1[2]=5

arr2[1]=x
arr2[2]=y

s=$(paste <(printf "%s\n" "${arr1[@]}") <(printf "%s\n" "${arr2[@]}") |
    tr '[[:space:]]' ' ')
echo "$s"
2 x 5 y

answered Dec 29, 2014 at 6:07

anubhava

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2 Comments

Rakib Over a year ago

Perfect! Thanks. One quick question, with tr, are you removing extra space? Because it seems to work even without the tr.

anubhava Over a year ago

Yes I am just removing extra whitespaces (space/tab/newlines) etc with tr. You can skip it also.

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