Use of php array related functions_PHP tutorial

There is no need to talk about the array() function when creating an array

To extract an array, you can use list().

To test array elements, you can use is_array()

Accepts a parameter, the variable passed in, if the variable is an array, returns true, if not, returns false.

Add and remove array elements

fifo and lifo of array

First explain what fifo and lifo are

Deleting elements is in the same order as adding elements, which is called first-in-first-out, that is, first-in-first-out

Deleting elements is in the opposite order to adding elements, which is called last-in-first-out, that is, last-in-first-out

Corresponding operations on arrays

• array_unshift()
• int aray_unshift(array array,mixed variable [,mixed variable...])

When you add an element to the head of the array, all existing numerical keys will change accordingly to reflect the new position in the array, and the associated keys will not be affected.

Example:

$words = array('a','b','c');

print_r($words);

//array([0]->a,[1]->b,[2]->c);

array_unshift($words,'d');

print_r($words);

//array([0]->d,[1]->a,[2]->b,[3]->c);

• array_shift()
• mixed array_shift(array array)

Removing an element from the head of the array removes and returns the element found in the array, with the result that if a numeric key is used, all corresponding values ​​are shifted down. If an associative key is used, the array is unaffected.

Example:

$words = array('a','b','c');

print_r($words);

//array([0]->a,[1]->b,[2]->c);

array_shift($words,'a');

print_r($words);

//array([0]->b,[1]->c);

• array_push()
• int array_push(array array,mixed variable [,mixed variable...])

Add elements from the end of the array and add variables to the end of the array. Return true if successful and false if failed. You can pass multiple parameters as input and push multiple variables into the array at the same time.

Example:

$stack = array("orange", "banana");
array_push($stack, "apple", "raspberry");
print_r($stack);
?>

This example will make $stack have the following units:

Array ( [0] => orange [1] => banana [2] => apple [3] => raspberry )

-------------------------------------------------- ---------------

For array operations, use $array[]=, which can increase efficiency because there is no need to call functions.

-------------------------------------------------- --

• array_pop()
• mixed array_pop(array target_array)

Removes an element from the end of the array and returns the last element of the array.

$stack = array("orange", "banana", "apple", "raspberry");
$fruit = array_pop($stack);
print_r($stack);
?>

After this operation, $stack will only have 3 cells:

Array ( [0] => orange [1] => banana [2] => apple )

Some of my own summaries and opinions.

The above four functions may be very useful sometimes. Let’s talk about the return value first

Note that the return value of array_unshift() and array_push() should be of boolean type, but the manual and related books indicate that the returned value is int type. This is worth thinking about.

The two functions array_shift() and array_pop() can not only delete the elements of the relevant array, but also return the deleted array elements. I will write it here first, there will be more to come. Let’s summarize slowly.

http://www.bkjia.com/PHPjc/371925.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/371925.htmlTechArticleThere is no need to talk about creating an array anymore. The array() function can use list() to extract an array. To test array elements, you can use is_array() accepts a parameter, the passed in variable, if the variable is an array, returns tru...