Re: test_v doesn't work for associative arrays

[Chet Ramey]

On 6/10/16 8:53 AM, pskocik@gmail.com wrote:

> Bash Version: 4.3
> Patch Level: 11
> Release Status: release
> 
> Description:
>       [Detailed description of the problem, suggestion, or complaint.]
> 
> Repeat-By:
> #!/bin/bash
> declare var
> declare -a ary
> declare -A asoc
> 
> var=1
> ary=(1)
> asoc[a]=1
> 
> for a in var ary asoc; do
>    printf '%s\t' "$a"
>    if test -v "$a"; then
>      echo ✓
>    else
>      echo ✗ 
>    fi
> done
> 
> <<OUTPUTS
> var   ✓
> ary   ✓
> asoc  ✗
> OUTPUTS

Referencing an array variable without a subscript is equivalent to
referencing element 0 (or "0" for associative arrays).  Plus, `test -v'
works on variable names, not dereferenced variables or array elements.

You can test whether or not a specific element is set by testing
whether it is non-empty (test -v 'ary[1]'), or test whether an array has
any elements set using something like [ ${#ary[@]} -gt 0 ].

One of the things that may come into a future version is something like
test -v 'array[@]' to see whether or not an array has any elements set.

Chet

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/