applying zsh qualifiers on array elements or directly on a result of a command substitution - zsh

Question

I did
a=( pacman -Qlq packagename )
to put files belonging to package into array
Why is this printing only the frist match, and how to print them all in zsh:
print -l ${a[(r)*i*]}
Also, how to apply zsh qualifiers on all array elements, say to list files
only via (.)
Is there an easier way to skip intermediary array in this process,
in a way to have qualifier specified on a result of a command substition?

Answer 1

As per documentation the subscript flag (r) will only return the first matching array element.
In order to get all matching elements you can use the {name:#pattern} parameter expansion, which removes any element maching pattern from the expansion. In order to remove the non-matching elements you can either use the flag (M) or negate the pattern with ^ (this requires the EXTENDED_GLOB option to be enabled):
print -l ${(M)a:#*i*}
setopt extendedglob
print -l ${a:#^*i*}
You can skip explicitly creating an intermediary array by just using the parameter expansion on the command substitution ($(...)) directly:
print -l ${(M)$(pacman -Qlq packagename):#*i*}
It seems that globbing qualifiers do not work with patterns inside parameter expansions. But you can enable the RC_EXPAND_PARAM option to expand every single array element within a word instead of the whole array. So foo${xx}bar with x=(a b c) will be expanded to fooabar foobbar foocbar instead of fooa b cbar. You can enabley it either globally with setopt rcexpandparam or for a specific expansion by wrapping it in ${^...}. This way you can add a glob qualifier to each element of the filtered array. To print only elements that are paths to files, you can use
print -l ${^${(M)$(pacman -Qlq packagename):#*i*}}(.N)
This essentially takes each path and attaches (.N) as glob qualifier (which works, even though there are no globs). The resulting patterns are then evaluated as part of filename generation. . tells zsh to only match plain files. N enables the NULL_GLOB option for these patterns, otherwise the command would abort with an "no matches found" error, if it encounters a pattern that is not a plain file (e.g. /usr is a directory, so /usr(.) does not match any plain file on your system.).