1、向array中添加元素
php是一个弱类型语言。因此不必象c语言那样为php array声明长度。向其中添加元素的过程也是声明和初始化的过程。
复制代码 代码如下:
$capitals = array(
"Alabama" => "Montgomery",
"Alaska" => "Juneau",
"Arizona" => "Phoenix"
);
继续添加元素也很简单
复制代码 代码如下:
$capitals["Arkansas"] = "Little Rock";
如果不是关联数组而只是数字索引的数组可以使用array_push()和array_unshift()函数增加元素
2、从array中删除元素
从数组中移除元素可以使用unset() 函数
复制代码 代码如下:
unset($capitals["California"]);
也可以使用array_pop()或array_shift()函数从数组头或尾部顺序移除元素
3、array键值互换
如果希望新建数组的键是老数组的值而值是老数组的键，简而言之就是键值对调，则可以使用array_flip()函数完成操作
复制代码 代码如下:
$capitals = array(
"Alabama" => "Montgomery",
"Alaska" => "Juneau",
"Arizona" => "Phoenix"
);
$states = array_flip($capitals);
// $states = array(
// "Montgomery" => string "Alabama",
// "Juneau" => string "Alaska",
// "Phoenix" => string "Arizona"
// );
4、合并数组
如果希望将两个或多个数组合并成一个新的数组，array_merge()函数可以帮上这个忙^_^
复制代码 代码如下:
$stateCapitals = array(
"Alabama" => "Montgomery",
"Alaska" => "Juneau",
"Arizona" => "Phoenix"
);
$countryCapitals = array (
"Australia" => "Canberra",
"Austria" => "Vienna",
"Algeria" => "Algiers"
);
$capitals = array_merge($stateCapitals, $countryCapitals);
5、修改array中的值
譬如希望将数组的中值全部改为小写后大写首字母，使用回调函数递归地对每个数组成员调用是个不错的方法，php中这个函数是php_map()
复制代码 代码如下:
function capitalize($element)
{
$element = strtolower($element);
return ucwords($element);
}
$capitals = array(
"Alabama" => "montGoMEry",
"Alaska" => "Juneau",
"Arizona" => "phoeniX"
);
$capitals = array_map("capitalize", $capitals);
6、根据array的键为数组排序
复制代码 代码如下:
$capitals = array(
"Arizona" => "Phoenix",
"Alaska" => "Juneau",
"Alabama" => "Montgomery"
);
ksort($capitals);
7、随机化array元素的顺序
shuffle() 和上面的ksort()函数恰恰相反，可以打乱数组现有的秩序，以达到随机化的目的。
复制代码 代码如下:
$capitals = array(
"Arizona" => "Phoenix",
"Alaska" => "Juneau",
"Alabama" => "Montgomery"
);
shuffle($capitals);
8、查找键或值是否存在
查找是否存在值使用in_array()函数
复制代码 代码如下:
$capitals = array(
"Arizona" => "Phoenix",
"Alaska" => "Juneau",
"Alabama" => "Montgomery"
);
if (in_array("Juneau", $capitals))
{
echo "Exists!";
} else {
echo "Does not exist!";
}
查找是否存在键使用array_key_exists()函数
复制代码 代码如下:
$capitals = array(
"Arizona" => "Phoenix",
"Alaska" => "Juneau",
"Alabama" => "Montgomery"
);
if (array_key_exists("Alaska", $capitals))
{
echo "Key exists!";
} else {
echo "Key does not exist!";
}
9、数组查找
这个是老生常谈了，基本上都用的到array_search()函数
复制代码 代码如下:
$capitals = array(
"Arizona" => "Phoenix",
"Alaska" => "Juneau",
"Alabama" => "Montgomery"
);
$state = array_search("Juneau", $capitals);
// $state = "Alaska"
10、使用php标准函数库
一口气介绍这个多操作array的函数，如果您还觉得不过瘾，可以继续查看Standard PHP Library 中的内容^_^
复制代码 代码如下:
$capitals = array(
"Arizona" => "Phoenix",
"Alaska" => "Juneau",
"Alabama" => "Montgomery"
);
$arrayObject = new ArrayObject($capitals);
foreach ($arrayObject as $state => $capital)
{
printf("The capital of %s is %s<br />", $state, $capital);
}
// The capital of Arizona is Phoenix
// The capital of Alaska is Juneau
// The capital of Alabama is Montgomery
