Re: [LUG] regexp?

[Simon Waters <Simon@xxxxxxxxxxxxxxxxxxxx>]

Adrian Midgley wrote:
> NHS Numbers are 10 digits.
> The canonical formatting of them is
> 999 999 9999
>
> However often they are present as
> 9999999999
>
> I am always amazed by the cleverness of people who can produce regexps such
> as one that would enable me to grep all lines out of a big text (csv, values
> in "") file which contain a specific NHS number regardless of which format it
> is presented in...

Sometimes it is easier to process the number format before you
write the regular expression. What did our Perl guru say about
write once code ;)

#!/bin/bash
#
# Program expectsd 10 digit number and greps for all occurances
of
# the same 10 digit number in double quotes.
# 
# Both input and found format may be 123 456 7890 or 1234567890
#
#  Simon Waters 2002
# 
if [ $# -ne 2 -a $# -ne 4 ]
then
echo "Usage $0 123 456 7890 myfile"
echo "   or $0 1234567890 myfile"
if [ $# -eq 2 ]
then
FIRST=`expr $1 : "\(...\)"` 
SECOND=`expr $1 : "...\(...\)"`
THIRD=`expr $1 : "......\(....\)"`
FILE=$2
fi
if [ $# -eq 4 ]
then
FIRST=$1
SECOND=$2  
THIRD=$3
FILE=$4
fi
grep -E "\"$FIRST $SECOND $THIRD\"|\"$FIRST$SECOND$THIRD\""
$FILE

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