Iterate over two arrays simultaneously in bash

Question

I have two arrays.

array=(   Vietnam   Germany   Argentina ) array2=(   Asia   Europe   America ) 

I want to loop over these two arrays simulataneously, i.e. invoke a command on the first elements of the two arrays, then invoke the same command on the second elements, and so on. Pseudocode:

for c in ${array[*]} do   echo -e " $c is in ......" done 

How can I do this?

Answer 1

From anishsane's answer and the comments therein we now know what you want. Here's the same thing in a bashier style, using a for loop. See the Looping Constructs section in the reference manual. I'm also using printf instead of echo.

#!/bin/bash  array=( "Vietnam" "Germany" "Argentina" ) array2=( "Asia" "Europe" "America" )  for i in "${!array[@]}"; do     printf "%s is in %s\n" "${array[i]}" "${array2[i]}" done 

Another possibility would be to use an associative array:

#!/bin/bash  declare -A continent  continent[Vietnam]=Asia continent[Germany]=Europe continent[Argentina]=America  for c in "${!continent[@]}"; do     printf "%s is in %s\n" "$c" "${continent[$c]}" done 

Depending on what you want to do, you might as well consider this second possibility. But note that you won't easily have control on the order the fields are shown in the second possibility (well, it's an associative array, so it's not really a surprise).

Answer 2

If all of the arrays are ordered correctly just pass around the index.

array=(   Vietnam   Germany   Argentina ) array2=(   Asia   Europe   America )  for index in ${!array[*]}; do    echo "${array[$index]} is in ${array2[$index]}" done  Vietnam is in Asia Germany is in Europe Argentina is in America