How to combine two arrays in php

In PHP, we can use the array_merge() function to merge two arrays into a new array. This function accepts any number of arrays as arguments, passed in any order. The syntax for using this function is as follows:

$new_array = array_merge($array1, $array2);

where $array1 and $array2 are the two arrays to be combined.

It should be noted that if the key values ​​​​of the two arrays are the same, the value of the latter array will overwrite the value of the previous array. If the array has values ​​of different types, the values ​​will retain their current type in the new array. If you want to ensure that the resulting new array has consecutive numerical indices, you can use another function array_merge_recursive().

$new_array = array_merge_recursive($array1, $array2);

This function is similar to array_merge(), but it can handle duplicate key values ​​and generate nested arrays within new arrays.

Here are some sample codes:

$array1 = array('a', 'b', 'c');
$array2 = array('d', 'e', 'f');
$result = array_merge($array1, $array2);
print_r($result); // 输出 Array ( [0] => a [1] => b [2] => c [3] => d [4] => e [5] => f )

$array1 = array('a' => 1, 'b' => 2, 'c' => 3);
$array2 = array('d' => 4, 'b' => 5, 'f' => 6);
$result = array_merge($array1, $array2);
print_r($result); // 输出 Array ( [a] => 1 [b] => 5 [c] => 3 [d] => 4 [f] => 6 )

$array1 = array('a' => 1, 'b' => 2, 'c' => 3);
$array2 = array('d' => 4, 'b' => 5, 'f' => 6);
$result = array_merge_recursive($array1, $array2);
print_r($result); // 输出 Array ( [a] => 1 [b] => Array ( [0] => 2 [1] => 5 ) [c] => 3 [d] => 4 [f] => 6 )

In some cases, you may need to combine two arrays according to certain rules. To achieve this, you can use the array_combine() function. This function takes values ​​from one array as keys, values ​​from another array as values, and returns a new array. This function requires two parameters, the key array and the value array to be converted.

$keys = array('a', 'b', 'c');
$values = array(1, 2, 3);
$result = array_combine($keys, $values);
print_r($result); // 输出 Array ( [a] => 1 [b] => 2 [c] => 3 )

In practical applications, combining arrays is a very useful technique. You can combine two arrays into one for manipulation and separate them when needed. In addition, combined arrays can also be used in parsing CSV files, creating form fields, etc.

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