Photoshop learning experience PHP learning array definition and filling

PHP arrays, to put it bluntly, mean that each array of associated data is saved in the form of [index, value]. The index defaults to a number starting from 0. When no index is specified, PHP will automatically generate the index starting from 0. When specifying an index, PHP will start at the integer next to the largest positive integer at the index you specify. If you specify a decimal, PHP will take the integer part as the index.
　Also let’s talk about some other little things about arrays:
array() can declare an empty array;
array[] = $value When the array exists, append a data; when the array does not exist, generate an array and append the data.
array[$index] = $value When the array exists, append or modify a data; when the array does not exist, generate an array and append the data.
Look at the code below:

Copy the code The code is as follows:

// Declare array
$test01 = array();
// Append data
$test01[] = "a"; // array (0 => "a");
//Append a data with index "a" and data "b"
$test01["a"] = "b"; // array(0 => " a", "a" => "b");
// Modify the data with index 0
$test01[0] = "c"; // array(0 => "c", "a" = > "b");
// Another way to declare
$test02 = array("a", "b", "c"); // array(0 => "a", 1 => "b", 2 => "c");
// Although a string indexed data is declared, the default index still starts from 0
$test03 = array("a" => "a", " b", "c"); // array("a" => "a", 0 => "b", 1 => "c");
// The maximum index in the declaration is 2, Although the index is 0 recently, the default index still starts from 3
$test04 = array(2 => "a", 0=>"b", "c"); // array(2 => " a", 0 => "b", 3 => "c");
// Declaring a decimal index will take the integer part; when specifying the index, the previously declared value will be modified
$test05 = array(" a", 2.7=>"b", 0=>"c"); // array(0 => "c", 2 => "b");
// Although a negative index is declared, But the default index still starts from 0
$test06 = array(-2 =>"a", "b", "c"); // array(-2 => "a", 1 => "b ", 2 => "c");
// Definition of multi-dimensional array
$test07 = array($test01, $test02, $test03);

　 Then introduce some filling functions of the array, most of which can be found in the manual I found it online, so I only give a brief introduction.
range($n, $m); specifies the range of values. For example, range(2,4) generates array array(2,3,4).
count($array); Get the size of the array.
array_pad($array, $length, $value); Returns an array with a length of $length. The original missing array is filled with $value, and the length is enough to return the original array.

The above introduces the definition and filling of arrays in photoshop learning experience and PHP learning, including the content of photoshop learning experience. I hope it will be helpful to friends who are interested in PHP tutorials.