Question

如果汽车数组中的数组的第3个元素为真，我想将其他元素设置为真。如何实现呢？

<?php 
  $cars = array
          (
          array(1,1,'f'),
          array(2,2,'f'),
          array(3,3,'t'),
          array(4,4,'f')
          );

        foreach($cars as $keys){
            if($keys[2]=='t')
           $count=1;
       }

        foreach($cars as $keys){
          if($count==1)
             $keys[2] = 't';
        }
        print_r($cars);
   ?>

Answer 1

如下所述，只需更改2件事，请尝试：

$cars = array
  (
  array(1,1,'f'),
  array(2,2,'f'),
  array(3,3,'t'),
  array(4,4,'f')
  );
$count = 0; // declare $count
foreach($cars as $keys){
    if($keys[2]=='t')
        $count=1;
}
foreach($cars as $key=>$keys){
  if($count==1)
     $cars[$key][2] = 't'; // change value to t like this
}

输出：

Array
(
    [0] => Array
        (
            [0] => 1
            [1] => 1
            [2] => t
        )

    [1] => Array
        (
            [0] => 2
            [1] => 2
            [2] => t
        )

    [2] => Array
        (
            [0] => 3
            [1] => 3
            [2] => t
        )

    [3] => Array
        (
            [0] => 4
            [1] => 4
            [2] => t
        )

)

Answer 2

你几乎接近，只需进行此更改，使用参考符号&进行实际更改

来自

foreach($cars as $keys){

到

foreach($cars as &$keys){

请检查：https://eval.in/609879

Answer 3

$exists= false;
foreach($cars as $car)
{
    if($car[2] == 't')
    {
        $exists= true;
    }
}

if($exists)
{
    for($i=0; $i<count($cars); $i++)
    {
        $cars[$i][2] = 't';
    }
}

Answer 4

以下是您的解决方案

<?php

$cars = array(
    array(1,1,'f'),
    array(2,2,'f'),
    array(3,3,'t'),
    array(4,4,'f')
);

if(in_array('t', array_column($cars, 2))){
    $cars = array_map(function($v){
        $v[2] = 't';
        return $v;
    }, $cars);
}

在数组数组中设置元素

4 个答案: