Use the array function to create a new array in PHP, phparray function array_PHP tutorial

Use the array function in PHP to create a new array. The phparray function array

The array in PHP is actually an ordered map. A map is a type that associates values ​​to keys. This type is optimized in many ways, so it can be treated as a real array, or list (vector), hash table (which is an implementation of map), dictionary, set, stack, queue and many more possibilities. Since the value of an array element can also be another array, tree structures and multidimensional arrays are also allowed.

array

(PHP 4, PHP 5)

array — Create a new array

Description

Copy code The code is as follows:
array array ([ mixed $... ] )

Returns an array created based on the parameters. Parameters can be indexed using the => operator. For information on what an array is please read the Arrays section.

Note:

array() is a language construct used to represent arrays literally, not a regular function.

The syntax "index => values", separated by commas, defines the index and value. The index can be a string or a number. If the index is omitted, an integer index starting from 0 is automatically generated. If the index is an integer, the next resulting index will be the largest integer index so far, 1. Note that if two identical indexes are defined, the latter one will overwrite the previous one.

Although it is unusual, it is legal syntax to add a comma after the last defined array item.

The following example demonstrates how to create a two-dimensional array, how to assign key names to the corresponding array, and how to skip and continue numeric indexes in ordinary arrays.

Example #1 array() Example

<&#63;php
$fruits = array (
  "fruits" => array("a" => "orange", "b" => "banana", "c" => "apple"),
  "numbers" => array(1, 2, 3, 4, 5, 6),
  "holes"  => array("first", 5 => "second", "third")
);
?>

Example #2 Automatic indexing of array()

<&#63;php
$array = array(1, 1, 1, 1, 1, 8 => 1, 4 => 1, 19, 3 => 13);
print_r($array);
?>

The above routine will output:

Array
(
[0] => 1
[1] => 1
[2] => 1
[3] => 13
[4] => 1
[8] => 1
[9] => 19
)

Note that index 3 is defined twice, retaining the last value of 13. Index 4 is defined after index 8, and the next automatically generated index (the one with value 19) is 9 because the largest index is 8.

This example creates an array starting from 1.

Example #3 array() indexed starting from 1

<&#63;php
$firstquarter = array(1 => 'January', 'February', 'March');
print_r($firstquarter);
?>

The above routine will output:

 Array
(
  [1] => January
  [2] => February
  [3] => March
)

In Perl, you can access the value of an array within double quotes. But in PHP, arrays need to be enclosed in curly braces.

Example #4 Accessing an array within double quotes

<&#63;php
$foo = array('bar' => 'baz');
echo "Hello {$foo['bar']}!"; // Hello baz!
?>

PHP Array function

PHP: Indicates the earliest PHP version that supports this function.

Function	Description	PHP
array()	Create an array.	3
array_change_key_case()	Returns an array whose keys are all uppercase or lowercase.	4
array_chunk()	Split an array into new array blocks.	4
array_combine()	Create a new array by merging two arrays.	5
array_count_values()	Used to count the number of occurrences of all values ​​in the array.	4
array_diff()	Returns the difference array of two arrays.	4
array_diff_assoc()	Compare the key name and key value, and return the difference array of the two arrays.	4
array_diff_key()	Compare key names and return the difference array of the two arrays.	5
array_diff_uassoc()	Calculate the difference set of arrays by doing index checking through the callback function provided by the user.	5
array_diff_ukey()	Use the callback function to compare the key names and calculate the difference set of the array.	5
array_fill()	Fills the array with the given values.	4
array_filter()	Use callback function to filter the elements in the array.	4
array_flip()	Swap the keys and values ​​in the array.	4
array_intersect()	Calculate the intersection of arrays.	4
array_intersect_assoc()	Compare the key name and key value and return the intersection array of the two arrays.	4
array_intersect_key()	Calculate the intersection of arrays using key name comparison.	5
array_intersect_uassoc()	Calculate the intersection of arrays with index checking, and use callback functions to compare the indices.	5
array_intersect_ukey()	Use callback function to compare key names to calculate the intersection of arrays.	5
array_key_exists()	Checks whether the given key or index exists in the array.	4
array_keys()	Returns all key names in the array.	4
array_map()	Apply the callback function to the cells of the given array.	4
array_merge()	Combine one or more arrays into one array.	4
array_merge_recursive()	Recursively merge one or more arrays.	4
array_multisort()	Sort multiple arrays or multidimensional arrays.	4
array_pad()	Pall the array to the specified length with values.	4
array_pop()	Pop the last element of the array (pop off the stack).	4
array_product()	Calculate the product of all values ​​in an array.	5
array_push()	Push one or more cells (elements) to the end of the array (push).	4
array_rand()	Randomly select one or more elements from the array and return it.	4
array_reduce()	Use a callback function to iteratively reduce the array to a single value.	4
array_reverse()	Reverse the order of elements in the original array, create a new array and return it.	4
array_search()	Search for the given value in the array and return the corresponding key name if successful.	4
array_shift()	Deletes the first element in the array and returns the value of the deleted element.	4
array_slice()	Retrieve a value from the array based on the condition and return it.	4
array_splice()	Remove part of the array and replace it with other values.	4
array_sum()	Calculate the sum of all values ​​in an array.	4
array_udiff()	Use callback function to compare data to calculate the difference of arrays.	5
array_udiff_assoc()	Calculate the difference set of arrays with index checking, and use callback functions to compare data.	5
array_udiff_uassoc()	Calculate the difference set of the array with index check, and use the callback function to compare the data and index.	5
array_uintersect()	Calculate the intersection of arrays and use callback functions to compare data.	5
array_uintersect_assoc()	Calculate the intersection of arrays with index checking and use callback functions to compare data.	5
array_uintersect_uassoc()	Calculate the intersection of arrays with index checking, and use callback functions to compare data and indexes.	5
array_unique()	Remove duplicate values ​​from the array.	4
array_unshift()	Insert one or more elements at the beginning of the array.	4
array_values()	Returns all values ​​in the array.	4
array_walk()	Apply a user function to each member of the array.	3
array_walk_recursive()