PHP: Find string in file and print the next few characters - php

Question

[amount] = "58"
I have a large text file, and am trying to find where amount occurs and print the 58, as I am scraping HTML on multiple pages, all with similar layouts, but the amount value changes on each page. The only constant is that the string [amount] occurs once, so I am able to use it to find the number value.
I would like to know how to do this in PHP.
Thanks.
The code I tried with was
$filename = 'site.txt';
$searchfor = '[amount]';
$file = file_get_contents($filename);
if(strpos($file, $searchfor [$offset = 6]))
{
echo $searchfor;
}

Answer 1

I guess you want to find the number 58, this can be done e.g.
input was site.txt:
some text [amount] = "58" some other text
running on cli: php test.php:
<?php
$filename = './site.txt';
$searchfor = '[amount]';
$file = file_get_contents($filename);
foreach( explode("\n", $file) as $line ){
$found = strpos($line, $searchfor);
if($found){
echo "string found on position: ".$found." in '" . $line. "'\n";
echo "so the searched stuff should be: '" . explode('"', substr($line,$found,strlen($line)-$found))[1] ."'\n";
}
}
?>
results in output:
string found on position: 10 in 'some text [amount] = "58" some other text'
so the searched stuff should be: '58'

Answer 2

$filename = 'site.txt';
$searchfor = '[amount] = "';
$file = file_get_contents($filename);
//find the position
$pos = strpos($file, $searchfor);
//check for real false here
if($pos!==false) {
//print from the found postion+lengthofserachfor
//(int) makes an real number if you get '6 abc' an real 6
echo (int)substr($file,$pos+strlen($searchfor),5);
}
So far, done.
if(preg_match('#amount\][ ]?=[ ]?"([0-9]+)#',$file,$matches)){
print_r($matches);
}
Have a nice day.