A summary of methods for converting a PHP two-dimensional array (or any array of dimensions) into a one-dimensional array

Directory

• 1 Array_reduce Function method
• 2 Array_walk_recursive Function method
• 3 Array_map Function method

Suppose you have the following two-dimensional array:

$user =Array' 0 ' + =Array' id ' =100,' Username ' =' A1 '),' 1 ' + =array ( ' id ' = 101,  username ' =  ' A2 '),  ' 2 ' + array ( ' id ' = 102,  username ' +  ' A3 '),  ' 3 ' = Span class= "Hljs-keyword" >array ( ' id ' = 103,  username ' =  ' A4 '),  ' 4 ' + array ( ' id ' = 104,  username ' +  ' A5 ');        

Now to convert to a one-dimensional array, there are two things:

One is to convert the specified column into a one-dimensional array, which is summarized in another article: PHP Extracts a multidimensional array of methods to specify a column.

Now let's focus on the second case, which is to convert all the values into one-dimensional arrays, and the same key values will not be overwritten, and the converted one-dimensional array would be:

Array (' A5 ');

There are several methods.

1 array_reduce Function Method

Using the Array_reduce () function is a faster method:

($result, $value) {    Array ())

Because the array_merge function merges the arrays of the same string key names, you must first use the array_value fetch values and then merge them.

If the second dimension is a numeric key name, such as:

Array (Array (    ' A1 '), Array (Array (array (    ' A5 '),);    

So that's it for you:

Array ())

2 array_walk_recursive Function Method

With the array_walk_recursive () function, it is very flexible to convert an array of any dimension into a one-dimensional array.

function(& $result) {    Array_push ($result, $value);});

For example, the following multidimensional array:

Array (Array (    ' A1 '), Array (Array (    ' A4 '      ),);

With this method, it becomes:

Array (' A4 ');

3 Array_map Function Method

In array_map array_reduce the same way as the function, as follows:

$result = [];array_map (& $result) {    $result = Array_merge ($result, Array_values ($ value));}, $user);

Just need to declare an empty $result array more.

In addition, the method can be used, array_walk and the foreach cyclic method, the principle and the same as above.

A summary of methods for converting a PHP two-dimensional array (or any array of dimensions) into a one-dimensional array