How do i remove last particular string using regex?

Question

Hi i have the string like below,

$aa = "Ability: N/S,Session: Session #2: Tues June 14th - Fri June 24th (9-2:00PM),Time: 10:30am,cname: karthi";

$aa = "Ability: N/S,Session: Session #1: Tues May 31st - Fri June 10th (1-5:30PM),Time: #1 only: 1:30pm,cname: ravi";

$aa = "Ability: N/S,Session: Session #1: Tues May 31st - Fri June 10th (1-5:30PM),Time: #1 only: 1am,cname: mathi";

i need to write single regex for removing the particular string from ",cname:" upto last. i need output like,

$aa = "Ability: N/S,Session: Session #2: Tues June 14th - Fri June 24th (9-2:00PM),Time: 10:30am";

    $aa = "Ability: N/S,Session: Session #1: Tues May 31st - Fri June 10th (1-5:30PM),Time: #1 only: 1:30pm";

    $aa = "Ability: N/S,Session: Session #1: Tues May 31st - Fri June 10th (1-5:30PM),Time: #1 only: 1am";

how can i do this in regex?

Btw, you don't want to remove everything after ",cname:". You want to keep the last semicolon. — m0skit0
– m0skit0, Commented Mar 2, 2012 at 13:19
yes i need semi colon.. i put semicolon for php format. thats it. actually the string is between the quotes. — Ravichandran Jothi
– Ravichandran Jothi, Commented Mar 2, 2012 at 13:20
If the string will always be in the same format, you don't need regex - you can simply $new = substr($str, 0, strpos($str, ',cname')); — DaveRandom
– DaveRandom, Commented Mar 2, 2012 at 13:21

rodneyrehm · Accepted Answer · 2012-03-02 13:20:45Z

1

You don't need regex for this. You can use strpos() to find the index of ',cname:' and then substr() up to that index.

<?php

$aa = "Ability: N/S,Session: Session #1: Tues May 31st - Fri June 10th (1-5:30PM),Time: #1 only: 1am,cname: mathi";
$pos = strpos($aa, ',cname:');
$bb = substr($aa, 0, $pos);
echo $bb, "\n";

but if you, for whatever reason, insist on using regex for this, you'll want to use preg_replace():

<?php

$aa = "Ability: N/S,Session: Session #1: Tues May 31st - Fri June 10th (1-5:30PM),Time: #1 only: 1am,cname: mathi";
$bb = preg_replace('#,cname:.*$#', '', $aa);
echo $bb, "\n";

and if you don't want to modify the string, you may want to use preg_match():

<?php

$aa = "Ability: N/S,Session: Session #1: Tues May 31st - Fri June 10th (1-5:30PM),Time: #1 only: 1am,cname: mathi";
if (preg_match('#^(.+),cname:.*$#', $aa, $match)) {
    echo $match[1], "\n";
}

answered Mar 2, 2012 at 13:20

rodneyrehm

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3 Comments

m0skit0 Over a year ago

Longer code = more potential bugs. Regex is shorter and cleaner.

rodneyrehm Over a year ago

For people knowing regular expressions they may seem cleaner. For those not too firm with regex, it just looks like mumbo jumbo. You also cannot argument against performance. Often times plain-string-function approaches outrun regex performance-wise. For this particular problem, I'd personally not have chosen regex.

m0skit0 Over a year ago

Still: longer code = more bugs. Not knowing a technique is no excuse for not using it. If they look like mumbo jumbo, then learn so they don't.

stema · Accepted Answer · 2012-03-02 13:20:25Z

1

Try

/,cname:.*$/

and replace with an empty string.

$result = preg_replace('/,cname:.*$/', '', $aa);

See it here on Regexr

answered Mar 2, 2012 at 13:20

stema

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1 Comment

m0skit0 Over a year ago

Unnecessary replace operation.

m0skit0 · Accepted Answer · 2012-03-02 13:28:26Z

0

/^(.*),cname:.*;$/

Group 1 ($1) generated by this regex will give you the result you want.

edited Mar 2, 2012 at 13:28

answered Mar 2, 2012 at 13:19

m0skit0

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1 Comment

DaveRandom Over a year ago

There is no semi-colon in the OP's string.

Toto · Accepted Answer · 2012-03-02 13:41:55Z

0

If you have more than one ,cname:... and just want to remove the last one, use this:

$aa= preg_replace('/,cname:.*?$/', '', $aa);

answered Mar 2, 2012 at 13:41

Toto

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