使用正则表达式使用php打印文件中字符串的所有出现

Question

i am writing a code that will print all instances of a string from a file of about 500 pages. This is some of the code:

$file = "serialnumbers.txt";
$file_open = fopen($file, 'r');

$string = "\$txtserial";
$read = fread($file_open,'8000000');
$match_string = preg_match('/^$txtserial/', $read, $matches[]=null);
for($i = 0; sizeof($matches) > $i; $i++)
{
echo "<li>$matches[$i]</li>";
}

All of the serial numbers start with "$txtserial" followed by about 10 numerical characters, some of them separated by comma(,). Example: $txtserial0840847276,8732569089. I am actually looking for a way to print every instances of the $txtserial with the following numerical characters excluding the comma(,). Though I have used regular expressions but if there is any other method to employ i will also be grateful. I just want to get this done in the quickest possible time

Answer 1

You have a problem here where you are trying to create a regex using string variable:

$match_string = preg_match('/^$txtserial/', $read, $matches[]=null);

You can use:

$match_string = preg_match('/^' . preg_quote($txtserial) . '/', $read, $matches);

Answer 2

Try this example using preg_match_all() function:

$txtserial = 'MSHKK';
$read = 'MSHKK1231231231,23
MSHKK1231231
txtserial123123109112
MSHKK1231231111,123123123';

$match_string = preg_match_all('/(?:^|(?<=[\n\r]))('.preg_quote($txtserial).'\d{10})\b/', $read, $matches);
print_r($matches[1]);

Output:

[0] => MSHKK1231231231
[1] => MSHKK1231231111

It is basically picking the portions which are starts with the value that $txtserial holds and followed by 10 digits.