有一些问题与php数组算法 - Having some trouble with php array algorithm

Having some trouble with php array algorithm

本文关键字：php 数组算法问题 | 更新日期: 2023-09-27

我不擅长算法。这就是我的烦恼。

我有一个数组:

$test_arr = array(
  0 => 'a',
  1 => 'b',
  2 => 'c',
  3 => 'd',
  4 => 'e',
  5 => 'f',
  6 => 'g',
  7 => 'h',
  8 => 'i',
);

如何用这样的算法重新排序:

$test_arr = array(
  0 => array(
    'a', 'b',
  ),
  1 => array(
    'c', 'd',
  ),
  2 => array(
    'e', 'f'
  ),
  3 => array(
    'g', 'h',
  ),
  4 => array(
    'i',
  ),
);

提前感谢!

PHP已经有一个内置函数来完成完全相同的任务。即array_chunk()

试试这个:

<?php
$test_arr = array(
0 => 'a',
1 => 'b',
2 => 'c',
3 => 'd',
4 => 'e',
5 => 'f',
6 => 'g',
7 => 'h',
8 => 'i',
);
var_dump(array_chunk($test_arr, 2));
?>

这是你正在寻找的算法:

$test_arr = array(
  0 => 'a',
  1 => 'b',
  2 => 'c',
  3 => 'd',
  4 => 'e',
  5 => 'f',
  6 => 'g',
  7 => 'h',
  8 => 'i',
);
$tmp_array = [];
$new_array = [];
$i = 1;
foreach($test_arr as $k => $v){
    if($i % 2 == 0){
        $tmp_array[] = $v;
        $new_array[] = $tmp_array;
        $tmp_array = [];
    }else{
        $tmp_array[] = $v;
    }
    $i++;
}
if(count($tmp_array) > 0){
    $new_array[] = $tmp_array;
}

echo '<pre>';
print_r($new_array);

此解决方案循环遍历给定数组，并仅在当前键为0或偶数时将当前值和下一个值保存到新数组。

<?php
$test_arr = array(
  0 => 'a',
  1 => 'b',
  2 => 'c',
  3 => 'd',
  4 => 'e',
  5 => 'f',
  6 => 'g',
  7 => 'h',
  8 => 'i',
);
$newarray = array();
foreach( $test_arr as $key => $value){
    if ( ($key == 0) || (($key % 2) == 0)){ 
        if( isset($test_arr[($key + 1)]) ) { $next = $test_arr[($key + 1)]; } else { $next = ''; }
        $newarray[] = array($value,  $next);
    }
}
echo print_r($newarray, true);
?>

结果

Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )
    [1] => Array
        (
            [0] => c
            [1] => d
        )
    [2] => Array
        (
            [0] => e
            [1] => f
        )
    [3] => Array
        (
            [0] => g
            [1] => h
        )
    [4] => Array
        (
            [0] => i
            [1] => 
        )
)