topic Re: Numeric validation in Operating System - HP-UX

Numeric validation

bhoang — Thu, 14 Feb 2002 22:35:35 GMT

Is there an existing shell script out there to check for a 3 digit field to be numeric?
TIA.

Re: Numeric validation

James R. Ferguson — Thu, 14 Feb 2002 22:38:58 GMT

Hi:

This is one method:

#!/usr/bin/sh
typeset X=$1
if [ `expr "$X" : '[0-9,\-]*'` -ne `expr "$X" : '.*'` ]
then
echo "not a number!"
else
echo "ok, is a number!"
fi
#.end.

Regards!

...JRF...

Re: Numeric validation

Steven Sim Kok Leong — Fri, 15 Feb 2002 02:21:55 GMT

Hi,

Here is another method:

#/sbin/sh
expr `echo $1|awk -F\. '{print $1$2}'` + 0
if [ "$?" != 0 ]
then
echo is NOT a number
else
echo is a number
fi

Hope this helps. Regards.

Steven Sim Kok Leong

Re: Numeric validation

Wodisch — Fri, 15 Feb 2002 04:08:59 GMT

Hello,

this one is faster since no additional processes are started:

case "$1" in
[0-9][0-9][0-9]) echo "3digit numeric" ;;
*) echo "NOT 3digit numeric" ;;
esac

HTH,
Wodisch

Re: Numeric validation

Steven Sim Kok Leong — Fri, 15 Feb 2002 04:14:57 GMT

Hi,

I agree with Wodisch, if only plain 3-digit places are required. If you want to also take care of decimal places and negatives, JRF's script takes care of them and any number of digits. Mine too.

Hope this helps. Regards.

Steven Sim Kok Leong

Re: Numeric validation

Peter Kloetgen — Fri, 15 Feb 2002 07:42:44 GMT

Hi,

there is a possibility which is even faster:

if (($1+1)) >/dev/null 2>&1
then
echo "$1 is a number!"
else
echo "$1 is something else
fi

Allways stay on the bright side of life!

Peter

Re: Numeric validation

Robin Wakefield — Fri, 15 Feb 2002 08:13:26 GMT

...and another way, n is the number of digits to look for:

# a=123
# n=3
echo $a | grep -E "^[0-9]{$n}$"
123
# n=4
# echo $a | grep -E "^[0-9]{$n}$"
#

Rgds, Robin.