Bash and key value pair or a map

Question

We are writing a bash script which basically does the job of python dictionary. Below is the code siffet we are using and the expected output.

#!/bin/bash
declare -A serviceTag
serviceTag["source"]="ccr"
declare -A services
services+=( ["dataservice"]="latest" )

serviceTag+=( ["services"]=services )

echo "$serviceTag"

The expected output is

{"source":"ccr","services":{"datasetvice":"latest"}}

But what we are getting is

ccrservices

Can somebody help us in what mistake we are doing here and how can we achieve this using bash and its code?

Regards, Kanthu

That and services is just the string services - you need array expansion for that as well. — muru, Mar 26 '20 at 11:23
Sorry, I didnt get it. Can you pls suggest me the code changes? — Kanthu Canty, Mar 26 '20 at 11:30
printf '{"%s":"%s","%s":"%s":{"%s":"%s"}}\n' "${!serviceTag[@]}" "${serviceTag[@]}" "${!services[@]}" "${services[@]}" — Jetchisel, Mar 26 '20 at 11:31
Using $avar instead of ${avar[@]} with an array avar refers to its first entry, not to the whole array, and you are NOT getting that output (ccrservices) from the code you have posted. But, as already said, bash's arrays are unidimensional, so that will not work, anyways. — , Mar 27 '20 at 02:02
Thaks Mosvy for your comment. If its an unidimensional, then I will have to look for other options on scripting. — Kanthu Canty, Mar 27 '20 at 04:03

Thomas Blankenhorn · Answer 1 · 2020-03-27T07:18:11.407

2

According to the GNU project's Bash reference manual, Bash's arrays are one-dimensional, whether they be indexed or associative. That means you can't nest them. Sorry to be the bearer of bad news, but I don't think what you're trying to do is possible.

edited Mar 27 '20 at 07:18

answered Mar 27 '20 at 01:23

Thomas Blankenhorn

169
4

Thanks Thomas for the clarification. – Kanthu Canty Mar 27 '20 at 04:04

score 0 · Answer 2 · answered Mar 26 '20 at 11:40

0

Not sure but you can try.

printf '{"%s":"%s","%s":"%s":{"%s":"%s"}}\n' "${!serviceTag[@]}" "${serviceTag[@]}" "${!services[@]}" "${services[@]}"

answered Mar 26 '20 at 11:40

Jetchisel

1,264

This is ending up with {"ccrservices":"ccrservices","latest":"latest":{"":""}} – Kanthu Canty Mar 26 '20 at 11:41
How can I access this this with key value pair.. ?? – Kanthu Canty Mar 26 '20 at 11:42
really, my output is what you're looking for. – Jetchisel Mar 26 '20 at 11:46
Yes, your suggested printf I am trying and ended up wih {"0":"ccrservices","0":"latest":{"":""}} output. But this not we are looking. We are expecting {"source":"ccr","services":{"datasetvice":"latest"}}. – Kanthu Canty Mar 26 '20 at 12:07
The output you posted is what I get on this side. – Jetchisel Mar 26 '20 at 12:09
Otherwise I would not have posted my answer... I have tested on both my linux machines and FreeBSD both have bashv5+. – Jetchisel Mar 26 '20 at 12:10
Strange. I am using MAC and bas version GNU bash, version 5.0.16(1)-release (x86_64-apple-darwin17.7.0) – Kanthu Canty Mar 26 '20 at 12:12
You might have 2 bash installed since the default bash on Mac is bashv3. Make sure you're really using bashv5+, try type -a bash and see what is the output. – Jetchisel Mar 26 '20 at 12:14
Here is the output along with bash version. – Kanthu Canty Mar 26 '20 at 12:20
5.0.16(1)-release {"source":"services","ccr":"services":{"0":"latest"}} KAVIRUPA-M-J0NZ:microk8s-deployments kavirupa$ KAVIRUPA-M-J0NZ:microk8s-deployments kavirupa$ – Kanthu Canty Mar 26 '20 at 12:21

score 0 · Answer 3 · answered Mar 27 '20 at 01:35

This isnt a task thats appropriate for shell scripting. Do yourself a favor, and use a programming language for this task. For example with PHP:

<?php
$services = ['dataservive' => 'latest'];
$serviceTag['source'] = 'ccr';
$serviceTag['services'] = $services;
# example 1
print_r($serviceTag);
# exmaple 2
echo json_encode($serviceTag), "\n";

Result:

Array (
   [source] => ccr
   [services] => Array (
      [dataservive] => latest
   )
)
{"source":"ccr","services":{"dataservive":"latest"}}

Bash and key value pair or a map

3 Answers3