Introducing several new functions of the array library_PHP tutorial

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We don’t have much PHP information on hand. Does everyone have a copy of php4gb.chm? What I appreciate most is the function library part, the real online help. But the pace of PHP development is too fast. Look, I recently found some extended array functions at www.php.net/manual/.

Let me introduce them to you below. My English level is not high. Please correct me if there are any mistakes in translation.
The format is like this:

Function name Supported version

Function declaration
Description, parameters, return value

Example


OK, Let's go.

//************************
array_flip (PHP4 >= 4.0b4)

array array_flip (array trans)

Swapping the key and value of the array trans means that the key becomes value and the value becomes key.
Returns the processed array.

Example:
$a[0]="abc";
$a[1]="def";
After an array_flip() you get:
$a["abc"]=0; $a["def"]=1;

//******************************
array_count_values ​​(PHP4 >= 4.0b4)

array array_count_values ​​(array input)
Count the number of each value in the input array. Returns an array with the input value as the key and a new array with the number of occurrences as the value.

Example:
$array = array (1, "hello", 1, "world", "hello");
array_count_values ​​($array);
// returns array (1=>2, "hello"=>2, "world"=>1)

//******************************
array_merge (PHP4)

array array_merge (array array1, array array2 [, array ...])
Merge multiple arrays and add the contents of array2 after array1. Returns an array of results.
If it is an associative array, with a string as the key, and a key with the same name appears, the later one will overwrite the previous one, while the subscript array will not be overwritten, but will be added at the end.

Example:
$array1 = array ("color" => "red", 2, 4);
$array2 = array ("a", "b", "color" => "green", "shape" => "trapezoid", 4);
array_merge ($array1, $array2);
//Resulting array will be array("color" => "green", 2, 4, "a", "b", "shape" => "trapezoid", 4).

See also array_merge_recursive().

//******************************
array_merge_recursive (PHP4 >= 4.0.1)

array array_merge_recursive (array array1, array array2 [, array ...])
Recursively merge arrays, basically similar to the previous function. The difference is that in terms of associative arrays, it does not simply merge the same keys, but generates a two-dimensional array to merge the values ​​of the same keys. (Sorry for not being able to express clearly, let’s look at examples).

Example:
$ar1 = array ("color" => array ("favorite" => "red"), 5);
$ar2 = array (10, "color" => array ("favorite" => "green", "blue"));
$result = array_merge_recursive ($ar1, $ar2);

//Resulting array will be array ("color" => array ("favorite" => array ("red", "green"), "blue"), 5, 10).


Got it? red and green are merged into a new array and placed in favorite.

See also array_merge().

//******************************
array_intersect (PHP4 >= 4.0.1)

array array_intersect (array array1, array array2 [, array ...])
Takes the intersection of multiple arrays and returns a new array containing the intersection elements.
It is based on array1, so if it is an associative array, the key value is array1. See examples.

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