1. An array can store multiple values in a single variable
<?php
header("Content-type: text/html; charset=utf-8");//设置编码
$arr = array('one','two','three','four','five');
?>2. What is an array
An array is a special variable that can store multiple values in a single variable
Arrays can store multiple values in a single variable, and the values can be accessed based on keys
3. How to create an array in php
array () Function is used to create arrays
4. There are 3 arrays in php
(1). Arrays with numeric ID keys----numeric arrays
(2). Array with specified keys, each key is associated with a value -------Associative array
(3). Array containing one or more arrays---- ----Multidimensional array
Numeric array
<?php
$cars=array("Volvo","BMW","Toyota"); //创建一个名为 $cars 的数值数组，并给数组分配三个元素
echo "I like " . $cars[0] . ", " . $cars[1] . " and " . $cars[2] . ".";
?>
Associative array
Associative array is an array using the specified key that you assign to the array
<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
echo "Peter is " . $age['Peter'] . " years old.";
?>Traverse the association Array
<?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
//是使用foreach 遍历关联数组
foreach($age as $x=>$x_value){
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";
}
?>Traverse and print all values in the associative array
Multidimensional array
<?php
$arr = array(
array(
"www.taobao.com",
"www.baidu.com"
),
array(
"www.php.cn",
"www.tianmao.com"
)
);
print('<pre>');
print_r($arr);
print('</pre>');
?>
Get the array length----------count() function
In the following case, get the length of an array
<?php
$arr = array(1,2,3,4,5,6,7,8,9);
echo count($arr);
?>
Array sorting
Array sorting, There are functions for sorting arrays in php
1.sort() - Sort the array in ascending order
2.rsort() - Sort the array in descending order
3 .asort() - Sort the array in ascending order based on the value of the associative array
4.ksort() - Sort the array in ascending order based on the keys of the associative array
5.arsort() - Sort the array in descending order according to the value of the associative array
6.krsort() - Sort the array in descending order according to the key of the associative array
sort()
<?php
//升序
$arr = array(1,15,6,8,1,28,35,26,7);
sort($arr);
echo "<pre>";
print_r($arr);
echo "</pre>";
?>
##rsort()
<?php
//降序
$arr1 = array(1,15,6,8,28,35,26,7);
rsort($arr1);
echo "<pre>";
print_r($arr1);
echo "</pre>";
?>
##asort()<?php
//asort
$arr = array('a','b','c');
asort($arr);
echo "<pre>";
print_r($arr);
echo "</pre>";
?>
arsort()<?php
//arsort
$arr = array('a','b','c');
arsort($arr);
echo "<pre>";
print_r($arr);
echo "</pre>";
?>
ksort()<?php
//ksort
$arr = array('a'=>10,'b'=>5,'c'=>20);
ksort($arr);
echo "<pre>";
print_r($arr);
echo "</pre>";
?>
krsort()<?php
//krsort
$arr = array('a'=>10,'b'=>5,'c'=>20);
krsort($arr);
echo "<pre>";
print_r($arr);
echo "</pre>";
?>
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