What about preg_replace?

What about preg_replace?

$thumbMark = '200x200';$thumb =$r['thumb'];echo $r['thumb'].'
'; // http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg                //$thumb='http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg';$r['thumb'] = preg_replace('/_\d+x\d+/', '_' . $thumbMark,$thumb);echo $r['thumb'].'
'; // http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg

Why is the above replacement function invalid? but can it be replaced normally if "$ thumb" is assigned directly as follows?

$thumbMark = '200x200';$thumb =$r['thumb'];echo $r['thumb'].'
'; // http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg$thumb='http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg';$r['thumb'] = preg_replace('/_\d+x\d+/', '_' . $thumbMark,$thumb);echo $r['thumb'].'
'; // http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_200x200.jpg

Reply to discussion (solution)

Var_dump ($ r ['thumb']);
Post result

Var_dump ($ r ['thumb']);
Post result


String (85) "http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg"

The block code is as follows:

While ($ r = $ db-> fetch_array ($ result )){
$ R ['adddate'] = timetodate ($ r ['addtime'], 5 );
$ R ['editdate'] = timetodate ($ r ['edittime'], 5 );

If ($ lazy & isset ($ r ['thumb']) & $ r ['thumb']) {
$ ThumbMark = '100x100 ';
If ($ list = 1 ){
$ ThumbMark = '200x200 ';
}
$ Thumb = $ r ['thumb'];
Var_dump ($ r ['thumb']);
// Echo $ r ['thumb'].'
'; // Http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg
// $ Thumb = 'http: // response ';
$ R ['thumb'] = preg_replace ('/_ \ d + x \ d +/', '_'. $ thumbMark, $ thumb );
// Echo $ r ['thumb'].'
';


}

............
}

Check the value of $ list

Check the value of $ list

If ($ list = 1 ){
$ ThumbMark = '200x200 ';
Echo 'list: '. $ list; // list: 1
}

Normal

I didn't expect a strange problem when I first came into contact with PHP. is it an environment problem?

After removing the x in the middle of the regular "/_ \ d + x \ d +/", the system can replace the regular expression and output "begin ";

It's really strange. Who did this "x" trick provoke?

After removing the x in the middle of the regular "/_ \ d + x \ d +/", the system can replace the regular expression and output "begin ";

It's really strange. Who did this "x" trick provoke?
It indicates that your regular expression is faulty.

Then why do values be assigned directly, such:
$ Thumb = 'http: // response ';

No problem.

From what you gave, you can't see any errors. you are debugging them carefully.

Var_dump ($ r ['thumb']);
Post result


String (85) "http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg"
Your string contains only 76 characters. why is it string (85 )?

Something like regular expressions can only start from the source.
$ Str = '_100x100.jpg ';
Echo preg_replace ('/_/', '', $ str );
Echo preg_replace ('/_ \ d +/', ', $ str );
Echo preg_replace ('/_ \ d + x/', '', $ str );
Echo preg_replace ('/_ \ d + x \ d +/', '', $ str );
If you have any questions, please try again...

Var_dump ($ r ['thumb']);
Post result


String (85) "http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg"
Your string contains only 76 characters. why is it string (85 )?

This is really strange, and finally solved with the regular "/_ \ d +. {6} \ d +. In php functions, "x" may generate six unknown items. 85-76 = 9. it should be 9. the last three may be numbers.

It has been determined that "x" is converted to another 9 characters, which may be caused by different encodings.

It has been determined that "x" is converted to another 9 characters, which may be caused by different encodings.

Correct that the six "x" are generated correctly,

String (85) "http://img2.com.cn/images/2014/038/422/14058002224830.9000001763_100x100.jpg", 3 characters are manually deleted