如何使用正则表达式删除最后一个特定的字符串?

时间:2012-03-02 13:15:07

标签: php regex string

嗨我有如下字符串,

$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";

我需要编写单个正则表达式来从“,cname:”到最后删除特定字符串。 我需要输出,

$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";

我怎么能在正则表达式中这样做?

4 个答案:

答案 0 :(得分:1)

尝试

/,cname:.*$/

并替换为空字符串。

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

here on Regexr

答案 1 :(得分:1)

你不需要正则表达式。您可以使用strpos()查找“,cname:”的索引,然后使用substr()查找该索引。

<?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";

但如果您出于某种原因坚持使用正则表达式,那么您将需要使用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";

如果您不想修改字符串,可能需要使用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";
}

答案 2 :(得分:0)

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

此正则表达式生成的第1组($ 1)将为您提供所需的结果。

答案 3 :(得分:0)

如果您有多个,cname:...并且只想删除最后一个,请使用:

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