Mini challenge: PHP

Hello, coders! 💻

Here's another quick quiz.
Using PHP, how would you extract 878 from the string below?

$confFile = '/etc/nginx/sites-enabled/878.test.mysite.com.conf';

View my solution

Here’s a possible solution that leverages type juggling.

$confFile = '/etc/nginx/sites-enabled/878.test.mysite.com.conf';
$number = (int) basename($confFile);

basename removes everything before the rightmost / and returns 878.test.mysite.com.conf.
Then by taking advantage of PHP’s type juggling we convert that string to an int and are left with 878.

Happy coding! ⌨️

Comments

[leichengde]

<?php
$confFile = '/etc/nginx/sites-enabled/878.test.mysite.com.conf';
if(preg_match('/\d+/',$confFile,$arr)){
echo $arr[0];
}
?>

Other ways to extract numbers from strings in PHP

The first method, using regular expressions:

function findNum($str=''){
$str=trim($str);
if(empty($str)){return '';}
$reg='/(\d{3}(.\d+)?)/is';//Regular expression matching numbers
preg_match_all($reg,$str,$result);
if(is_array($result)&&!empty($result)&&!empty($result[1])&&!empty($result[1][0])){
return $result[1][0];
}
return '';
}

The second method, using the in_array method:

function findNum($str=''){
$str=trim($str);
if(empty($str)){return '';}
$temp=array('1','2','3','4','5','6','7','8','9','0');
$result='';
for($i=0;$i<strlen($str);$i++){
if(in_array($str[$i],$temp)){
$result.=$str[$i];
}
}
return $result;
}

The third method, using the is_numeric function:

function findNum($str=''){
$str=trim($str);
if(empty($str)){return '';}
$result='';
for($i=0;$i<strlen($str);$i++){
if(is_numeric($str[$i])){
$result.=$str[$i];
}
}
return $result;
}

[Julien Dephix]

You should wrap your code with triple backticks so it’s more readable.

Out of the three methods you posted the first one makes the most sense but the others are a fun take!

You can simplify your first findNum from:

if (is_array($result) && !empty($result) && !empty($result[1]) && !empty($result[1][0])) {
    return $result[1][0];
}
return '';

to

return $result[1][0] ?? ‘’;

Thanks for your answer!

[leichengde]

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