Splitting string into array

Question

I want to split the string and construct the array. I tried the below code:

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

Can you please advise?

Answer 1

I suggest you to read more at this sites:

• Ubuntu Forums
• Anton Olsen Blog

Study more and you will find the answer yourself, I also suggest you to read the Bash Reference Manual and in your future answers, please put more details. Thanks.

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 is to use awk entirely

Answer 3

Looks like you've already found the solution, but note that you can do away with awk entirely:

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

Answer 4

Here is how I would approach this problem: use the IFS variable to tell the shell (bash) that you want to split the string into colon-separated 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

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