mattmc3/split.zsh.md

## split.zsh.md

      
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              split.zsh.md
            
          
    There are a ton of different ways to split up a string in Zsh. This gist attempts to show
them with examples to help you build your own. I write Zsh scripts all the time, and still
reference back to this gist, so there you go.
From the Zsh docs on Parameter Expansion Flags (yeah - I know... how would anyone ever find that if they didn't know where to look!?)

j:string:  Join the words of arrays together using string as a separator.

s:string:  Force field splitting at the separator string.

You can also read more by running man zshexpn. (Again, I know, right!? How would anyone know to look there!?)
Example splitting a string on slash character in Zsh.
$ str=part1/part2/part3
$ parts=(${(@s:/:)str})
$ echo $parts
part1 part2 part3
$ echo ${#parts[@]}
3
You can use split ${(@s:/:)str} and indexing [start,end] to do more sophisticated surgery on string parts. Note that Zsh array indexing starts a 1, not 0.
If you need to reassemble, simply join back on the same separator ${(@j:/:)str}. Note: weirdly, the colons can be swapped out for other symbols, so if you prefer periods for example, this would also work: ${(@j./.)str}. Since I'm splitting on slashes, I choose not to use slash as my symbol.
$ url="https://github.com/sorin-ionescu/prezto/blob/master/modules/history/init.zsh"
$ repo="${(@j:/:)${(@s:/:)url}[4,5]}"
$ echo $repo
sorin-ionescu/prezto
An example from the Zsh docs which shows splitting. Note the use of slash below unlike the colon above to surround the split character - remember that symbol is swapable and doesn't change the behavior of the split at all:
$ foo=(ax1 bx1)
$ print -l -- ${(s/x/)foo}
a
1 b
1
Getting the first 2 parts
$ str=a/b/c/d/e/f
$ parts=(${(@s:/:)str})
$ echo ${(@j:/:)parts[1,2]}
a/b
You can also use # and % parameter expansion symbols: see docs. # removes from the left side, and % from the right, which I remember by the fact that # is to the left of % on your actual keyboard. ## and %% use the longest match, while # and % use the shortest.
$ str=part1/part2/part3
$ echo ${str%%/*}
part1
$ echo ${str%/*}
part1/part2
$ echo ${${str%/*}#*/}
part2
$ echo ${str#*/}
part2/part3
$ echo ${str##*/}
part3
Word splitting is done with the '=' character:
$ sentence="ls -l -A -h"
$ arr=(${=sentence})
$ print -l -- $arr
ls
-l
-A
-h