如何从数组元素中获取后续元素？

Question

I am trying to get a specific line in a file and then next 2 lines after it. How can I get next 2 lines? The following is my code and file.

$context = 'context=regencyoutgoing';
$lines = file('/etc/asterisk/sip1.conf');
foreach($lines as $line)
{
    $find_context = strpos($line, $context);
    if($find_context !== false){
        echo $line;
    }
}   

Here is my sip1.conf:

[000201891]
type=friend
context=regencyoutgoing
username=000201891
callerid = <000201891>
host=dynamic
secret=198



[000202222]
type=friend
context=regencyoutgoing
username=000202222
callerid = <000202222>
host=dynamic
secret=2000

Answer 1

This should work for you:

First of all we get all array elements, which contain $context somewhere with preg_grep(). In your example something like this:

Array
(
    2  => context=regencyoutgoing
    12 => context=regencyoutgoing
)

After this we get the keys of the array with array_keys(). Then we simply loop through all keys and take a slice of 3 elements for each key with array_slice(), which we then merge to the result array with array_merge().

Code:

 <?php

    $lines = file("/etc/asterisk/sip1.conf");
    $context = "context=regencyoutgoing";
    $matchedKeys = array_keys(preg_grep("/" . preg_qute($context, "/")  ."/", $lines));
    $result = [];

    foreach($matchedKeys as $key)
        $result = array_merge($result, array_slice($lines, $key, 3));

    print_r($result);

?>