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Home: Perl Programming Help: Beginner:
Regular expression to grep the contetnts of a file.

Raju_P
Novice

Dec 7, 2012, 11:15 PM

Post #1 of 4 (1799 views)

Regular expression to grep the contetnts of a file.	Can't Post

Hi,
Can some one assist me, how to write the regular expression to select the contents of a line from mytxt.txt file

Contents of mytxt.txt.
1. My Name, ID123
2. His Name, ID456
3. Her Name, ID789

By running the below program, by entering option 1, $Variable should be assigned with My Name, ID123
------------------------------------------------------------------------------------------------------

my (@list, $index, $variable, @user);
open(LIST, "mytxt.txt") or die "Cannot open mytxt.txt file. $!\n";
@list = <LIST>;
print @list;
close LIST;

print "Enter option: ";
#If option 1 is entered then $Variable should assign My Name, ID123.
#If option 2 is entered then $Variable should assign His Name, ID456.
chomp($index = <STDIN>);
while (@list)
{
chomp;
if (/(?<=$index.\s)(.+)/)---------> (I have used look behind option)
{
$Variable = $2;
}
}
print $Variable;

------------------------------------------------------------------------------------------------------------------

(This post was edited by Raju_P on Dec 8, 2012, 12:47 AM)

Laurent_R
Veteran / Moderator

Dec 8, 2012, 1:26 AM

Post #2 of 4 (1792 views)

Re: [Raju_P] Regular expression to grep the contetnts of a file. [In reply to]	Can't Post

Something like this should do it:

Code

my $id = $1 if /^$index\.\s+\w+\s+Name,\s(ID\d+)$/;

You might also consider reading the file first and storing the values in an array, in which $ID[1] would be "ID123", etc. You would then have direct access to the IDs.

Raju_P
Novice

Dec 8, 2012, 2:14 AM

Post #3 of 4 (1791 views)

Re: [Laurent_R] Regular expression to grep the contetnts of a file. [In reply to]	Can't Post

Laurent_R, Thanks for you reply. The earlier text file was just as example. The actal text file looks like somewhat in the below.

If I enter option 1.

print $Variable

Result:
John Murphy Philip, wer23v

Contents of mytxt.txt.
1. John Murphy Philip, wer23v
2. Michael Tan, qw5fc3
3. Nancy, 2v8jws

Laurent_R
Veteran / Moderator

Dec 8, 2012, 6:00 AM

Post #4 of 4 (1778 views)

Re: [Raju_P] Regular expression to grep the contetnts of a file. [In reply to]	Can't Post

For obtaning help on regexes, you should really provide examples on actual data, not just pseudo-data actually looking totally different. I just can't guess your data if you give me something else.

Code

my $id = $1 if /^$index\.[^,]+,\s+(\w{6})$/;

should match your new data. My assumptions about the data format (rules that I derive from your examples):
- the line has one and only one comma, which separates the name from the ID
- the ID code is made up of 6 alphanumerical characters and sits at the end of the line.

If these assumptions are wrong, then we need to refine further the regex.

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