Split a delimited string into multiple strings...

leeharris · 02-05-2009, 03:30 PM

I might be overlooking something really obvious here but...

I have a single string of text, with numerous commas in it. I want to parse the string, and use the comma as a delimeter to separate it into multiple strings hopefully just in shell scripting.

Example:

Input String...

value1,value2,value3,value4

Ouput Strings...

value1
value2
value3
value4

Any ideas?

Thanks - Lee

MensaWater · 02-05-2009, 04:00 PM

Code:

set `echo value1,value2,value3,value4 |awk -F, '{print $1,$2,$3,$4}'`
VAL1=$1
VAL2=$2
VAL3=$3
VAL4=$4
echo $VAL1
echo $VAL2
echo $VAL3
echo $VAL4

You use the -F flag in awk to tell it what to use for field separator (comma in this case).
The print statement with commas in it causes the output to have spaces instead of commas (odd isn't it?)
The set command populates the positional parameters ($1 through $n).
You then initialize arbitrary variable names (I chose VAL1 through VAL4 - you could choose bob, judy, ralph and david or whatever) by assigning each of the positional parameters to one of the arbitrary ones.
Lastly you simply echo each of the arbitrary variables which will show the value it now contains.

jan61 · 02-05-2009, 04:57 PM

Moin,

if you're within a bash, you can split the input using arrays:

Code:

jan@jack:~> IFS=',
> '
jan@jack:~> echo "value1,value2,value3,value4" | while read -a inp; do
> for member in ${inp[@]}; do
> echo $member
> done
> done
value1
value2
value3
value4

IFS defines the Input Field Separator, read -a reads all values of a line into an array. The for loop iterates over all elements of the array. It works also for multiple line input:

Code:

jan@jack:~> echo -e "value1,value2,value3,value4\nv5,v6\nval7,val8,val9" |
> while read -a inp; do 
> echo "new line"
> for member in ${inp[@]}; do
> echo $member
> done
> done
new line
value1
value2
value3
value4
new line
v5
v6
new line
val7
val8
val9

Jan

JulianTosh · 02-05-2009, 11:29 PM

For The Win...

echo value1,value2,value3 | tr "," "\n"

leeharris · 02-06-2009, 07:18 AM

Sorry should have explained this better... those options are all fine if I know how many variables there are. however, I want to do this on a string of an undetermined length.

One time it could be 1 string to 10 strings or 1 string to 500 strings or more.

JulianTosh · 02-06-2009, 07:55 AM

my solution works with any number of fields in the input string. tr or "translate" simply replaces all commas with carriage returns.

If the input strings are in a file, and you have multiple string (one per line), then you can do this:

cat inputStrings.txt | tr "," "\n"

If your inputString.txt file contains:

Quote:

value1,value2
value3,value4,value5,value6
value7
value8,value9,value10

The output would be:

Quote:

value1
value2
value3
value4
value5
value6
value7
value8
value9
value10

leeharris · 02-06-2009, 08:49 AM

Thanks all who replied... Admiral Beotch, your solution is genius! I just tried it and it works perfectly. As always, simplicity is the way to go :-)

A colleague of mine knocked this up in perl which also works, but isn't as eloquent as your single command approach...

#!/usr/bin/perl
$string=$ARGV[0];
@list= split(/,/,$string);
foreach $line (@list)
{
print "$line\n";
}

Nice.

Thanks - Lee

Telemachos · 02-06-2009, 11:44 AM

A perl one-liner. Replace 'file' with the name of the file:

Code:

perl -nle 'print "$_" foreach split /,/' file

jan61 · 02-06-2009, 02:30 PM

Moin,

just for justice ;-) As you see in my example, the array method works with different number of values too.

Jan

JulianTosh · 02-06-2009, 04:04 PM

Quote:

Originally Posted by In Russian accent:

In Soviet Russia, interpreted jan61 perl script is inferior speed to compiled 'tr' binary executable.

shyamkumar1986 · 02-07-2009, 06:10 AM

If you are planning on using Java - here is an example you can leverage:

http://www.exampledepot.com/egs/java.../Tokenize.html