split string to array where length is not fixed (not bash)

Question

How is it possible to split a string to an array?

#!/bin/sh

eg.

str="field 1,field 2,field 3,field 4"

The length of the arrays is various

Have found alot of solutions but they only works in bash

update

This only works if the length of the array has 4 values, but what if it has 10 values?

The for loop doesn't seem to work

arr=$(echo "field 1,field 2,field 3,field 4" | awk '{split($0,a,","); print a[1],a[2],a[3],a[4]}');

for value in ${arr[@]}
do
    echo "$value\n"
done

Answer 1

To get the split into variables in dash (that doesn't support arrays) use:

string="field 1,field 2,field 3,field 4"
IFS=","
set -- $string
for val
do
  echo "$val"
done

Answer 2

In bash you can do this:

str="field 1,field 2,field 3,field 4"
IFS=, array=($str)

IFS is the input field separator.

Zsh is much more elegant

array=${(s:,:)str}

You can even do it directly

% for i in "${(s:,:)str[@]}"; do echo $i; done
field 1
field 2
field 3
field 4