PHP array learning: how to create arrays by merging

In the previous article "PHP Array Learning: How to Create Arrays by Filling", we introduced two alternative methods of creating arrays. Here we introduce an alternative array creation method, let’s take a look.

We generally talk about merging two arrays, the type is like this:

有两个数组
array (size=2)
  'a' => string 'red' (length=3)
  'b' => string 'green' (length=5)
array (size=2)
  'c' => string 'blue' (length=4)
  'd' => string 'yellow' (length=6)
  
合并两个数组
array (size=4)
  'a' => string 'red' (length=3)
  'b' => string 'green' (length=5)
  'c' => string 'blue' (length=4)
  'd' => string 'yellow' (length=6)

Splice two arrays, append all the elements (key names and key values) of one array to the back of the other array .

But in fact, to merge two arrays, we can also use one array element as the key name and the other array element as the key value. In this way, we can create a new array.

Let’s take a look at the following example:

<?php
header("Content-type:text/html;charset=utf-8");
$keys=array("a","b","c","d");
$values=array("red","green","blue","yellow");
var_dump($keys);
var_dump($values);
echo "使用array_combine()合并数组后:";
var_dump(array_combine($keys,$values));
?>

The output result is:

It can be seen that, In the above example, the array_combine($keys,$values) function is used to create a new array by merging two arrays, in which the elements in the $keys array are used as the new array. The key name, the element of the $values array is used as the key value of the new array.

But it should be noted that when using the array_combine() function to create an array, the number of elements in the $keys array and the $values ​​array must be consistent, so that the key names and key values ​​can correspond one to one, otherwise An error will be reported and FALSE will be reported:

<?php
$keys=array("a","b","c","d");
$values=array("red","green","blue");
var_dump(array_combine($keys,$values));
?>

$keys array cannot be a multi-dimensional array

<?php
$keys=array(array("1","2","3"),"b","c","d");
$values=array("red","green","blue","yellow");
var_dump(array_combine($keys,$values));
?>

Otherwise, an error will be reported:

But the $values ​​array can be a multi-dimensional array

<?php
$keys=array("a","b","c","d");
$values=array(array("red","pink","orange"),"green","blue","yellow");
var_dump(array_combine($keys,$values));
?>

The output result is:

Okay, that’s it for now, there are other If you want to know, you can click this. → →php video tutorial

Finally, I would like to recommend a free video tutorial on PHP arrays: PHP function array array function video explanation, come and learn!

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