Detailed explanation of array_merge merging arrays in php, array_merge array

Detailed explanation of array_merge merging arrays in php, array_merge array_PHP tutorial

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Release： 2016-07-13 10:17:34

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Detailed explanation of array_merge merging arrays in php, array_merge array

If the key name is repeated, the key value of the key is the value corresponding to the last key name (the latter one overwrites the previous one) . If the array is numerically indexed, the key names are re-indexed consecutively.

Note: If only an array is input to the array_merge() function, and the keys are integers, the function will return a new array with integer keys, with keys re-indexed starting from 0.

The code is as follows. Copy the code

$a=array(3=>"Horse",4=>"Dog");
print_r(array_merge($a));
?>

Combine the cells of one or more arrays, and the values in one array are appended to the previous array. Returns the resulting array.

If there is the same string key name in the input array, the value after the key name will overwrite the previous value. However, if the array contains numeric keys, the subsequent values will not overwrite the original values, but will be appended to them.

If only an array is given and the array is numerically indexed, the key names are re-indexed consecutively.

Examples are as follows:

Copy the code as follows
$face = array("J","Q","K","A");
$numbered = array("2","3","4 ","5","6","7","8","9");
$cards = array_merge($face, $numbered);
shuffle($cards);
print_r($cards);

This will return results as shown below,

The code is as follows Copy the code
Array ( [0] => A [1] => 4 [2] => 9 [3] => 3 [4] => K [5] => 7 [6] => 5 [7] => Q [8] => 6 [9] => 8 [10] => 2 [11] => J )

Append arrays recursively
The array_merge_recursive() function is the same as array_merge(). It can merge two or more arrays together to form a combined array. The difference between the two is that the function will handle it differently when a key in an input array already exists in the result array. array_merge() will overwrite the previously existing key/value (www.111cn.net) pairs and replace them with the key/value pairs in the current input array, while array_merge_recursive() will merge the two values together to form a new array , and use the original key as the array name. There is also a form of array merging, which is to recursively append arrays. Its form is:

array array_merge_recursive( array key, array values )

An example is as follows:

Copy the code as follows
$array1 = array("AA"=>"A","BB"=>"B","CC"=>"C ","DD"=>"D");
$array2 = array("AA"=>"1","BB"=>"2","CC"=>"3" ,"DD"=>"4");
$array3 = array("AA"=>"!","BB"=>"@","CC"=>"#", "DD"=>"$");
$arrayX = array_merge($array1, $array2, $array3); //Merge arrays
print_r($arrayX);
?>

Concatenate two arrays

The array_combine() function will get a new array, which consists of a set of submitted keys and corresponding values. Its form is:

array array_merge(array array1,array array2[…,array arrayN])

Note that the two input arrays must be of the same size and cannot be empty. An example is as follows: