How to get the time difference corresponding to different values in php two-dimensional array

$arr=[
"0" =>["a1" => "true","time" => 1537861731],
"1" =>["a1" => "false","time" => 1541035671],
"2" =>["a1" => "true","time" => 1541036000],
"3" =>["a1" => "true","time" => 1541036010]
"4" =>["a1" => "false","time" => 1541036020]
 ];
 
 true:;
 
 false:;
 
 truefalse;
 falsetrue;
 
 
 
 :
 
 falsetrue
 
  1042
Php
Oct.11,2021

from your array, I feel that you are dealing strangely with the length of the call (referring to the way the array is formed).
you should be able to get the results you want with the following code: 

$true_key = null;
$times = [];
foreach ($arr as $key => $value) {

    if ($value['a1'] == 'true') {
        // true
        if ($true_key === null) {
            $true_key = $key;
        }
        continue;
    }

    /**
     * 
     */
    if (($value['a1'] == 'false') && ($true_key !== null)) {
        $times[]  = $value['time'] - $arr[$true_key]['time'];
        $true_key = null;
    }
}

first take apart true and false into groups .
then traverses a group of true . And iterate over a group that is false at the same time.
each iteration advances the cursor if the current end time is not null , the end time minus the start time is the connection time. 

$arr=[
    ['a1' => 'true','time' => 1537861731],
    ['a1' => 'false','time' => 1541035671],
    ['a1' => 'true','time' => 1541036000],
    ['a1' => 'true','time' => 1541036010],
    ['a1' => 'false','time' => 1541036020]
 ];

$start = [];
$finish = [];
foreach ($arr as $item) {
    if($item['a1']==='true'){
        array_push($start,$item);
        continue;
    }
    array_push($finish,$item);
}

$result = array_map(function($item)use(&$finish){
    $current = current($finish);
    next($finish);
    if($current){
        return $current['time'] - $item['time'];
    }
},$start);

var_dump($result);

Previous: The external network of the project built by vue-cli3.x cannot be hot updated.

Next: Can request cookie in python be used by selenium?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b39a63-3455e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b39a63-3455e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?