In-depth analysis of the difference between using the plus sign and using array_merge to merge arrays in PHP_PHP Tutorial

We first give two arrays

Copy code The code is as follows:

$r = array (1,2,3,4,5,6);
$e = array(7,8,9,10);
?>

Below we use array_merge Why bother with these two arrays

Copy code The code is as follows: r+e); // OutputArray ( [0] => 1 [1] => 2 [2] => ; 3 [3] => 4 [4] => 5 [5] => 6 )

print "
";

print_r(array_merge($ r,$e)); // OutputArray ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 )
?>


As you can see from here, array_merge is used to merge arrays. The values ​​in one array are appended to the previous array. Returns the resulting array. If the array contains numeric key names, subsequent values ​​will not overwrite the original values, but will be appended to them. However, use the plus sign to merge arrays. If the key names are the same, the array value that appears first will be taken, and the rest will be ignored
Let’s change the array given earlier

Copy code

The code is as follows: $r = array('r'=>1,2,3,4,5, 6);

$e = array('r'=>7,8,9, 10);

?>

Copy code

The code is as follows: print_r($r+e); // Output Array ( [r] => 1 [0] => 2 [1] => 3 [2] => 4 [3] => ; 5 [4] => 6 )

print "
";

print_r(array_merge($r,$e)); // Output Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [ 8] => 9 )
?>


As you can see from here, array_merge is used to merge arrays. The values ​​in one array are appended to the previous array. If the non-numeric key names are the same, the value of the subsequent array will overwrite the value of the previous array. However, if you use the plus sign to merge arrays, if the key names are the same, the array value that appears first will be taken, and the subsequent ones will be ignored

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truehttp: //www.bkjia.com/PHPjc/327214.htmlTechArticleWe first give two arrays to copy the code as follows: ?php $r = array(1,2,3 ,4,5,6); $e = array(7,8,9,10); ? Below we use array_merge and the plus sign to copy the code for these two arrays...