List specific elements of an array in bash

Question

I have an array something like this, array=( A B C D E F G H I J K L M N O P Q R S T U V W X Y Z) I would like to list values “b, e, o, u, z” I tried using:

`echo ${array[1,4,14, 20, 25]}`

[This command doesn’t work] The output be: B E O U Z I’m not looking for

echo ${array[1] array[4] array [14]...}

What would be the perfect command to get this output?

choroba · Accepted Answer · 2019-02-08 08:34:55Z

1

I haven't found a way without eval:

#! /bin/bash
array=( A B C D E F G H I J K L M N O P Q R S T U V W X Y Z )
x=(\${array[{1,4,14,20,25}]})
eval echo ${x[@]}

answered Feb 8, 2019 at 8:34

choroba

245k27 gold badges221 silver badges304 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Nahuel Fouilleul Over a year ago

sligthly better eval a=$ \"\${array[{1,4,14,20,25}]}\" $; echo "${a[@]}"

Mike Holt Over a year ago

Did I stumble into a code golf challenge? What's wrong with plain old printf "%s " ${array[1]} ${array[4]} ${array[14]} ${array[20]} ${array[25]} ?

Nahuel Fouilleul Over a year ago

otherwise without eval x=(); for i in 1 4 14 20 25; do x+=( "${array[i]}" ); done; echo "${x[@]}"

Nahuel Fouilleul Over a year ago

@MikeHolt, the question is more about array slicing than golfing, and seems you missed the double quotes, and how do you handle an arbitrary list of indices

Mike Holt Over a year ago

Easy enough to handle an arbitrary list of indices without using eval. I'm not in the "eval is evil, don't ever use it" camp (although the warnings about security are not without merit), but in this case it seems at best it saves you a slight amount of typing. Your own for loop example is plenty concise, and much clearer than the eval solution. Using eval just seems IMO like being needlessly clever. Not to mention the for loop will handle arbitrary lists of indices just fine.

Collectives™ on Stack Overflow

List specific elements of an array in bash

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related