Dividing a string into an array

Question

I want to split a string and build an array. I tried the code below:

myString="first column:second column:third column" set -A myArray `echo $myString | awk 'BEGIN{FS=":"}{for (i=1; i<=NF; i++) print $i}'` # Following is just to make sure that array is constructed properly i=0 while [ $i -lt ${#myArray[@]} ] do echo "Element $i:${myArray[$i]}" (( i=i+1 )) done exit 0 It produces the following result: Element 0:first Element 1:column Element 2:second Element 3:column Element 4:third Element 5:column This is not what I want it to be. When I construct the array, I want that array to contain only three elements. Element 0:first column Element 1:second column Element 2:third column 

Could you advise?

Answer 1

Here's how I would apply this problem: use the IFS variable to tell the shell (bash) that you want to split the string into colon tokens.

 $ cat split.sh #!/bin/sh # Script to split fields into tokens # Here is the string where tokens separated by colons s="first column:second column:third column" IFS=":" # Set the field separator set $s # Breaks the string into $1, $2, ... i=0 for item # A for loop by default loop through $1, $2, ... do echo "Element $i: $item" ((i++)) done 

Run it:

 $ ./split.sh Element 0: first column Element 1: second column Element 2: third column 

Answer 2

if you definitely want to use arrays in bash you can try this way

 $ myString="first column:second column:third column" $ myString="${myString//:/ }" #remove all the colons $ echo "${myString}" first column second column third column $ read -a myArr <<<$myString $ echo ${myArr[@]} first column second column third column $ echo ${myArr[1]} column $ echo ${myArr[2]} second 

Otherwise, the "better" method should use awk completely

Answer 3

Please note that saving and restoring IFS, as I often saw in these solutions, has a side effect: if IFS was not installed, it ends up changing to an empty string, which causes strange problems with subsequent splitting.

Here, the solution I developed based on Anton Olsen expanded to handle> 2 values ​​separated by a colon. It handles values ​​in a list that have spaces correctly, rather than being split into spaces.

 colon_list=${1} # colon-separate list to split while true ; do part=${colon_list%%:*} # Delete longest substring match from back colon_list=${colon_list#*:} # Delete shortest substring match from front parts[i++]=$part # We are done when there is no more colon if test "$colon_list" = "$part" ; then break fi done # Show we've split the list for part in "${parts[@]}"; do echo $part done 

Answer 4

Ksh or Bash

 #! /bin/sh myString="first column:second column:third column" IFS=: A=( $myString ) echo ${A[0]} echo ${A[1]} 

Answer 5

It looks like you have already found a solution, but note that you can completely remove awk:

 myString="first column:second column:third column" OIFS="$IFS" IFS=':' myArray=($myString) IFS=$OIFS i=0 while [ $i -lt ${#myArray[@]} ] do echo "Element $i:${myArray[$i]}" (( i=i+1 )) done