PHP中的数组

数组分类

1. 索引数组
2. 关联数组

数组遍历

1. 传值遍历
2. 传址遍历

数组函数

1. 指针操作函数

• current($array) 当前位置的内容
• key($array) 当前位置的键值
• next($array) 指针移动到下一个单元
• prev($array) 指针移动到上一个单元
• reset($array) 指针移动到第一个单元
• end($array) 指针移动到最后一个单元

2. 单元函数操作

• array_pop($array) 删除数组中的最后一个元素

<?php
$a=array("red","green","blue");
array_pop($a);
print_r($a);
?>

Array ( [0] => red [1] => green )

• array_push($array,$ele,$ele2) 数组尾部插N个元素

<?php
$a=array("red","green");
array_push($a,"blue","yellow");
print_r($a);
?>

Array ( [0] => red [1] => green [2] => blue [3] => yellow )

• array_shift($array) 删除数组中的第一个元素（red），并返回被删除元素的值

<?php
$a=array("a"=>"red","b"=>"green","c"=>"blue");
echo array_shift($a);
print_r ($a);
?>

redArray ( [b] => green [c] => blue )

• array_unshift($array,$ele) 把元素插入数组中

<?php
$a=array("a"=>"red","b"=>"green");
array_unshift($a,"blue");
print_r($a);
?>

Array ( [0] => blue [a] => red [b] => green )

• array_slice($array,2) 从数组的第三个元素开始取出，并返回数组中的其余元素

<?php
$a=array("red","green","blue","yellow","brown");
print_r(array_slice($a,2));
?>

Array ( [0] => blue [1] => yellow [2] => brown )

• array_splice($array,2,$要替换的元素) 把数组中的一部分去掉并用其它值取代,2后面的元素都去掉

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("a"=>"purple","b"=>"orange");
array_splice($a1,0,2,$a2);
print_r($a1);
?>

Array ( [0] => purple [1] => orange [c] => blue [d] => yellow )

• array_map('two',$array) 可以对数组中的每一个元素，按照two函数的规则操作返回一个新的数组

<?php
function myfunction($v)
{
  return($v*$v);
}

$a=array(1,2,3,4,5);
print_r(array_map("myfunction",$a));
?>

Array ( [0] => 1 [1] => 4 [2] => 9 [3] => 16 [4] => 25 )

• compact('变量名字','变量名字') 把多个变量的名字和内容，合成一个数组

<?php
$firstname = "Bill";
$lastname = "Gates";
$age = "60";

$result = compact("firstname", "lastname", "age");

print_r($result);
?>

Array ( [firstname] => Bill [lastname] => Gates [age] => 60 )

• extract($array) 把数组中的内容分解成一个一个变量

<?php
$a = "Original";
$my_array = array("a" => "Cat","b" => "Dog", "c" => "Horse");
extract($my_array);
echo "\$a = $a; \$b = $b; \$c = $c";
?>

$a = Cat; $b = Dog; $c = Horse

• array_merge($array,$array) 合成多个数组

<?php
$a1=array("red","green");
$a2=array("blue","yellow");
print_r(array_merge($a1,$a2));
?

Array ( [0] => red [1] => green [2] => blue [3] => yellow )

• array_chunk($array,2,true) 把数组分割为带有两个元素的数组

<?php
$cars=array("Volvo","BMW","Toyota","Honda","Mercedes","Opel");
print_r(array_chunk($cars,2));
?>

Array ( [0] => Array ( [0] => Volvo [1] => BMW ) [1] => Array ( [0] => Toyota [1] => Honda ) [2] => Array ( [0] => Mercedes [1] => Opel ) )

排序

1. sort 排序
2. asort 下标保留
3. ksort
4. usort
5. rsort
6. shuffle 乱序