php数组

October 31, 2020 2889

数组

数组是一个能在单个变量中存储多个值的特殊变量。

创建变量方法

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array()

创建数值数组

自动分配id键

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<?php 
$cars=array("Volvo","BMW","Toyota");
echo "I like".$cars[0].",".$cars[1]."and".$cars[2].".";
?>
  
/*输出结果:
I likeVolvo,BMWandToyota.

人工分配id键

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<?php 
$cars=array("Volvo","BMW","Toyota");
$cars[1]="Volvo";
$cars[2]="BMW";
$cars[3]="Toyota";
echo "I like".$cars[1].",".$cars[2]."and".$cars[3].".";
?>
  
/*输出结果:
I likeVolvo,BMWandToyota.

获取数组的长度

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<?php 
$cars=array("Volvo","BMW","Toyota");
echo count($cars); #count()函数用于返回数组的长度（元素的数量）
?> 

/*输出结果：3

遍历数值数组

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<?php 
$cars=array("Volvo","BMW","Toyota");
$arrlength=count($cars);

for($x=0;$x<$arrlength;$x++) #arrlength=array().length
{
	echo $cars[$x];
	echo "<br>";
}
?> 
  
/*输出结果：
Volvo
BMW
Toyota

关联数组

方法一

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<?php 
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43"); 
echo "Peter is " . $age['Peter'] . " years old."; 
?>
  
/*输出结果：Peter is 35 years old.

方法二

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<?php 
$age['peter']="35";
$age['ben']="37";
$age['joe']="43";
echo "Peter is " . $age['peter'] . " years old."; 
?> 
  
/*输出结果：Peter is 35 years old.

遍历关联数组

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<?php 
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43"); 

foreach($age as $x=>$x_value)
{
	echo "key=" . $x .",value=". $x_value;
	echo "<br>";
}
?>

/*输出结果：
key=Peter,value=35
key=Ben,value=37
key=Joe,value=43



数组排序

sort() 升序排列

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<?php 
$cars=array("Volvo","BWM","Toyota");
sort($cars);
print_r($cars);
?> 
  
  
  /*输出结果:
Array
(
    [0] => BWM
    [1] => Toyota
    [2] => Volvo
)
 
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<?php 
$numbers=array(4,6,2,22,11);
sort($numbers);
print_r($numbers);
?> 
  
  
 /*输出结果：
Array
(
    [0] => 2
    [1] => 4
    [2] => 6
    [3] => 11
    [4] => 22
)

rsort() 降序排列

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<?php 
$cars=array("Volvo","BWM","Toyota");
rsort($cars);
print_r($cars);
?> 
  
  
  /*输出结果：
Array
(
    [0] => Volvo
    [1] => Toyota
    [2] => BWM
)

asort() 根据数组的值进行升序排列

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<?php 
$age=array("peter"=>"35","ben"=>"37","joe"=>"43");
asort($age);
print_r($age);
?>

ksort() 根据数组的键进行升序排列

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<?php 
$age=array("peter"=>"35","ben"=>"37","joe"=>"43");
ksort($age);
print_r($age);
?>