BASH for loop multiple arrays

Question

I am trying to pull info from multiple arrays and then echo it out. Unfortunately, I am having some trouble and I am almost positive it is something wrong with my for loop structure.

Lets assume:

array1= 1, 2, 3
array2= toronto, new york, paris

The code that I currently have:

for element in "${array1[@]}" "${array2[@]}"
do
echo ""$element" "element""
done

The output looks something like this:

1 1
2 2
3 3
toronto toronto
new york new york
paris paris

Now this obviously doesn't work because it outputs the same thing twice in each array. So, I tried to use a for loop within a for loop but then I have multiples.

How would I setup the for loop so my output looks like this:

1 toronto
2 new york
3 paris

The definition array2= toronto, new york, paris is not valid at all if you want to define an array. — fedorqui
– fedorqui, Commented Dec 1, 2014 at 15:18
You can't natively loop over multiple arrays. So you have to manually do it by looping numerically from 0 to "${#array1}" (or "${#array1}" depending on which is longer and what behaviour you want if they don't have the same length). — Etan Reisner
– Etan Reisner, Commented Dec 1, 2014 at 15:22
just wanted to put down that the question itself answered what google brought me here for. I wanted to loop over two arrays (sequentially) and didn't know you could just concatenate them like that (for element in "${array1[@]}" "${array2[@]}"), I was about to attempt something silly (printf '%s\n' "${array1[@]}" "${array2[@]}" | while read.... gross). So thanks! — Hashbrown
– Hashbrown, Commented Jan 30, 2020 at 4:56

Gilles Quénot · Accepted Answer · 2014-12-01 15:22:17Z

4

array1= 1, 2, 3
array2= toronto, new york, paris

should be rewritten as :

array1=( 1 2 3 )
array2=( toronto 'new york' paris )

And finally :

for ((i=0; i<${#array1[@]}; i++)); do echo "${array1[$i]} ${array2[$i]}"; done

answered Dec 1, 2014 at 15:22

Gilles Quénot

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3 Comments

fedorqui Over a year ago

This is a very good way to do it. Simple and using the right tools, +1

msw Over a year ago

Yea this is unreal. Exactly what I was looking for. Very efficient!

ToiletGuy Over a year ago

Doesn't look good because u have to make sure that the array has similar naming

anubhava · Accepted Answer · 2014-12-01 15:22:26Z

1

You probably want this:

array1=(1 2 3)
array2=(toronto "new york" paris)
paste <(printf "%s\n" "${array1[@]}") <(printf "%s\n" "${array2[@]}")
1   toronto
2   new york
3   paris

answered Dec 1, 2014 at 15:22

anubhava

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Comments

g3stapoo · Accepted Answer · 2014-12-01 15:54:32Z

0

#!/bin/bash
declare -a arr2=("1" "2" "3")
declare -a arr=("element" "element" "element")
x=0
while [ $x -le 2 ]
do
echo " "${arr2[x]}" ${arr[x]}"
 x=$(( $x + 1 ))
done

answered Dec 1, 2014 at 15:54

g3stapoo

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2 Comments

GameDroids Over a year ago

some additional explanation to your solution would be nice (so other readers can understand it easier). On another matter: you might want to think about changing your user name, people could take it wrong and feel affronted, if you know what I mean.

g3stapoo Over a year ago

yes dude you are rigth I m newbies on linux and this webside. I try to learn just ask question myself how . and I know my nick means I don't accept their behavior even rock earth what else without soul did not deserve vulgarity . I hope my sences are clear eng is not my laguage

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