数组是一组有某种共同特性的元素，包括相似性和类型。
每个元素由一个特殊的标识符来区分，称之为key，而每个key都有一个value
1.创建数组的两种方式：
1.1 用array()函数
$usernames = array ("Alerk", "Mary", "Lucy", "Bob", "Jack", "John", "Mark" );
foreach ( $usernames as $name )
{
echo $name . "
";
}
?>
output
Alerk
Mary
Lucy
Bob
Jack
John
Mark
1.2 用range()函数
代码如下
$numbers = range ( 0, 10 );
foreach ( $numbers as $num )
{
echo $num . "
";
}
$letters = range ( "a", "z" );
foreach ( $letters as $letter )
{
echo $letter . "
";
}
?>
output
0
1
2
3
4
5
6
7
8
9
10
a
c
d
e
f
g
h
i
j
k
l
m
o
q
r
t
u
v
w
x
y
z
2.循环访问数组元素的两种方式:
2.1 for循环
//range的第三个参数表示步长
$numbers = range(1,10,2);
for($i = 0;$i
echo $numbers[$i]."
";
}
?>
output
1
3
5
7
9
2.2 foreach循环
代码如下
$letters = range("a","h",2);
foreach($letters as $letter)
{
echo $letter."
";
}
?>
output
a
c
e
g
Foreach还可以用来输出数组的下标和对应的值
代码如下
$letters = range("a","g",2);
foreach($letters as $key => $value)
{
echo $key."---".$value."
";
}
?>
output
0---a
1---c
2---e
3---g
3.is_array()函数，用于变量判断是否为一个数组
代码如下
$numbers = range(1,10,2);
if(is_array($numbers))
{
foreach($numbers as $num)
{
echo $num."
";
}
}
else
{
echo $numbers;
}
?>
4.print_r函数，打印关于变量的易于理解的信息
代码如下
$usernames = array ("Jackie", "Mary", "Lucy", "Bob", "Mark", "John" );
print_r ( $usernames );
?>
output
Array ( [0] => Jackie [1] => Mary [2] => Lucy [3] => Bob [4] => Mark [5] => John )
源代码里可以看到显示为：
Array
(
[0] => Jackie
[1] => Mary
[2] => Lucy
[3] => Bob
[4] => Mark
[5] => John
)
二．自定义键数组
1.如果不想创建默认下标为零的数组，可以用如下方法，创建键为字符串的数组
//初始化数组
$userages = array("Jack"=> 23,"Lucy"=>25,"Mark"=>28);
//访问数组各元素
echo $userages["Jack"]."
";
echo $userages["Lucy"]."
";
echo $userages["Mark"]."
";
?>
2.往自定义键数组里追加元素
代码如下
//初始化数组
$ages = array("Jack"=>23);
//追加元素
$ages["Lucy"]=25;
$ages["Mark"]=28;
foreach($ages as $key => $value)
{
echo $key."----".$value."
";
}
?>
3.直接添加元素，无需创建数组。
代码如下
//不创建数组直接添加
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
foreach($ages as $key => $value)
{
echo $key."----".$value."
";
}
?>
4.循环打印数组foreach的使用
代码如下
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
foreach($ages as $key => $value)
{
echo $key."=>".$value."
";
}
?>
5. each() -- 返回数组中当前的键／值对并将数组指针向前移动一步
代码如下
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
$a = each($ages);
print_r($a);
echo "
";
$a = each($ages);
print_r($a);
echo "
";
$a = each($ages);
print_r($a);
?>
用each()函数做循环打印
代码如下
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
while(!! $element = each($ages))
{
print_r($element);
echo "
";
}
?>
另一种打印方式
代码如下
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
while(!! $element = each($ages))
{
echo $element["key"]."=>".$element["value"];
echo "
";
}
?>
6.list()函数的使用--把数组中的值赋给一些变量
代码如下
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
list($name,$age)= each($ages);
echo $name."=>".$age;
?>
用list循环打印结果
代码如下
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
while(!!list($name,$age)= each($ages))
{
echo $name."=>".$age."
";
}
?>
output
Jack=>23
Lucy=>25
Mark=>28
7.reset()函数的使用--将数组的内部指针指向第一个单元
代码如下
$ages["Jack"]=23;
$ages["Lucy"]=25;
$ages["Mark"]=28;
each($ages);
each($ages);
list($name,$age)= each($ages);
echo $name."=>".$age."
";
//把数组重新设定到数组开始处
reset($ages);
list($name,$age)= each($ages);
echo $name."=>".$age."
";
?>
Output
Mark=>28
Jack=>23
8. array_unique() -- 移除数组中重复的值
代码如下
$nums = array(1,2,3,4,5,6,5,4,3,2,1,1,2,3,4,5,6);
//返回一个不包含重复值的数组
$result = array_unique($nums);
print_r($result);
?>
Output
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 )
9. array_flip ()-- 交换数组中的键和值
$userages = array("Jack"=> 23,"Lucy"=>25,"Mark"=>28);
$ages = array_flip($userages);
print_r($ages);
?>
output
Array ( [23] => Jack [25] => Lucy [28] => Mark )
三．数组里的数组
数组里不一定就是一个关键字和值的列表，数组里也可以放入数组
$produces = array(
array("apple",6,28.8),
array("pear",3,15.6),
array("banana",10,4.6)
);
echo $produces[0][0]."|".$produces[0][1]."|".$produces[0][2]."
";
echo $produces[1][0]."|".$produces[1][1]."|".$produces[1][2]."
";
echo $produces[2][0]."|".$produces[2][1]."|".$produces[2][2]."
";
?>
output
apple|6|28.8
pear|3|15.6
banana|10|4.6
用for循环打印数组中的数组
$produces = array (
array ("apple", 6, 28.8 ),
array ("pear", 3, 15.6 ),
array ("banana", 10, 4.6 )
);
for($i = 0; $i < count ( $produces ); $i ++)
{
for($j = 0; $j < count ( $produces [$i] ); $j ++)
{
echo "|" . $produces[$i][$j];
}
echo "
";
}
?>
output
|apple|6|28.8
|pear|3|15.6
|banana|10|4.6
二维数组
代码如下
$produces = array (
array ("name" => "apple", "amount" => 6, "price" => 28.8 ),
array ("name" => "pear", "amount" => 3, "price" => 15.6 ),
array ("name" => "banana", "amount" => 10, "price" => 4.6 )
);
while(!!List($key,$value)=each($produces))
{
while(!!list($key2,$value2)=each($value))
{
echo "|".$key2."=>".$value2;
}
echo "
";
}
?>
output
|name=>apple|amount=>6|price=>28.8
|name=>pear|amount=>3|price=>15.6
|name=>banana|amount=>10|price=>4.6
用foreach来打印则更容易（推荐）
代码如下
$produces = array (
array ("name" => "apple", "amount" => 6, "price" => 28.8 ),
array ("name" => "pear", "amount" => 3, "price" => 15.6 ),
array ("name" => "banana", "amount" => 10, "price" => 4.6 )
);
foreach($produces as $key1 => $value1)
{
foreach($value1 as $key2 => $value2)
{
echo "|".$key2."=>".$value2;
}
echo "
";
}
?>
output
|name=>apple|amount=>6|price=>28.8
|name=>pear|amount=>3|price=>15.6
|name=>banana|amount=>10|price=>4.6
四．数组的排序
1.Sort()函数对英文的排序
$fruits = array("lemo","banana","apple","pear");
echo "原始的数组：";
print_r($fruits);
echo "
";
sort($fruits);
echo "排序后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [0] => lemo [1] => banana [2] => apple [3] => pear )
排序后的数组：Array ( [0] => apple [1] => banana [2] => lemo [3] => pear )
2.Sort()函数对中文的排序
$fruits = array("柠檬","香蕉","苹果","梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
sort($fruits);
echo "排序后的数组：";
print_r($fruits);
?>
Output:
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
排序后的数组：Array ( [0] => 柠檬 [1] => 梨子 [2] => 苹果 [3] => 香蕉 )
3. asort -- 对数组进行排序并保持索引关系
$fruits = array("a"=>"柠檬","b"=>"香蕉","c"=>"苹果","d"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
asort($fruits);
echo "排序后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
排序后的数组：Array ( [a] => 柠檬 [d] => 梨子 [c] => 苹果 [b] => 香蕉 )
4. ksort -- 对数组按照键名排序
$fruits = array("b"=>"柠檬","a"=>"香蕉","d"=>"苹果","c"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
ksort($fruits);
echo "排序后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [b] => 柠檬 [a] => 香蕉 [d] => 苹果 [c] => 梨子 )
排序后的数组：Array ( [a] => 香蕉 [b] => 柠檬 [c] => 梨子 [d] => 苹果 )
5. rsort -- 对数组逆向排序
代码如下
$fruits = array("柠檬","香蕉","苹果","梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
rsort($fruits);
echo "排序后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
排序后的数组：Array ( [0] => 香蕉 [1] => 苹果 [2] => 梨子 [3] => 柠檬 )
6. arsort -- 对数组进行逆向排序并保持索引关系
$fruits = array("a"=>"柠檬","b"=>"香蕉","c"=>"苹果","d"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
arsort($fruits);
echo "排序后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
排序后的数组：Array ( [b] => 香蕉 [c] => 苹果 [d] => 梨子 [a] => 柠檬 )
7. krsort -- 对数组按照键名逆向排序
$fruits = array("a"=>"柠檬","b"=>"香蕉","c"=>"苹果","d"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
krsort($fruits);
echo "排序后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
排序后的数组：Array ( [d] => 梨子 [c] => 苹果 [b] => 香蕉 [a] => 柠檬 )
8. shuffle -- 将数组打乱
$fruits = array("a"=>"柠檬","b"=>"香蕉","c"=>"苹果","d"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
shuffle($fruits);
echo "打乱后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
打乱后的数组：Array ( [0] => 香蕉 [1] => 苹果 [2] => 柠檬 [3] => 梨子 )
9. array_reverse -- 返回一个单元顺序相反的数组
$fruits = array("a"=>"柠檬","b"=>"香蕉","c"=>"苹果","d"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
$fruits = array_reverse($fruits);
echo "反转后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
反转后的数组：Array ( [d] => 梨子 [c] => 苹果 [b] => 香蕉 [a] => 柠檬 )
10. array_unshift -- 在数组开头插入一个或多个单元
$fruits = array("a"=>"柠檬","b"=>"香蕉","c"=>"苹果","d"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
array_unshift($fruits,"?{子");
echo "插入后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
插入后的数组：Array ( [0] => ?{子 [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
11. array_shift -- 将数组开头的单元移出数组
$fruits = array("a"=>"柠檬","b"=>"香蕉","c"=>"苹果","d"=>"梨子");
echo "原始的数组：";
print_r($fruits);
echo "
";
array_shift($fruits);
echo "移出后的数组：";
print_r($fruits);
?>
output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
移出后的数组：Array ( [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
12. array_rand -- 从数组中随机取出一个或多个单元
$fruits = array ("柠檬", "香蕉", "苹果", "梨子" );
echo "原始的数组：";
print_r ( $fruits );
echo "
";
$newArr_key = array_rand ( $fruits, 2 );
echo "随机后的数组：";
echo $fruits [$newArr_key [0]]." ";
echo $fruits [$newArr_key [1]];
?>
output
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
随机后的数组：梨子 苹果
13. array_pop -- 将数组最后一个单元弹出（出栈）
$fruits = array ("柠檬", "香蕉", "苹果", "梨子" );
echo "原始的数组：";
print_r ( $fruits );
echo "
";
array_pop ( $fruits );
echo "弹出后的数组：";
print_r ( $fruits );
?>
Output:
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
弹出后的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 )
14. array_push -- 将一个或多个单元压入数组的末尾（入栈）
$fruits = array ("柠檬", "香蕉", "苹果", "梨子" );
echo "原始的数组：";
print_r ( $fruits );
echo "
";
array_push ( $fruits,"?{子");
echo "弹出后的数组：";
print_r ( $fruits );
?>
Output:
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
弹出后的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 [4] => ?{子 )
五．数组的指针的操作
each -- 返回数组中当前的键／值对并将数组指针向前移动一步
current -- 返回数组中的当前单元
reset -- 将数组的内部指针指向第一个单元
end -- 将数组的内部指针指向最后一个单元
next -- 将数组中的内部指针向前移动一位
pos -- current() 的别名
prev -- 将数组的内部指针倒回一位
$fruits = array ("柠檬", "香蕉", "苹果", "梨子" );
print_r ( $fruits );
echo "
";
echo "each() : ";
print_r ( each ( $fruits ) );
echo "
";
echo "current() : ";
echo (current ( $fruits ));
echo "
";
echo "next() : ";
echo (next ( $fruits ));
echo "
";
echo "end() : ";
echo (end ( $fruits ));
echo "
";
echo "prev() : ";
echo (prev ( $fruits ));
echo "
";
echo "pos() : ";
echo (pos ( $fruits ));
echo "
";
?>
Output:
Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
each() : Array ( [1] => 柠檬 [value] => 柠檬 [0] => 0 [key] => 0 )
current() : 香蕉
next() : 苹果
end() : 梨子
prev() : 苹果
pos() : 苹果
六．统计数组个数
count -- 计算数组中的单元数目或对象中的属性个数
sizeof -- count() 的别名
array_count_values -- 统计数组中所有的值出现的次数
$nums = array (1, 3, 5, 1, 3, 4, 5, 65, 4, 2, 2, 1, 4, 4, 1, 1, 4, 1, 5, 4, 5, 4 );
echo count ( $nums );
echo "
";
echo sizeof ( $nums );
echo "
";
$arrayCount = array_count_values ( $nums );
print_r ( $arrayCount );
?>
output
22
22
Array ( [1] => 6 [3] => 2 [5] => 4 [4] => 7 [65] => 1 [2] => 2 )
七．将数组转换成标量变量：extract()
把数组中的每个元素转换成变量，变量名是数组元素的key,变量值为数组元素的value.
$fruits = array("a"=>"apple","b"=>"banana","o"=>"orange");
extract($fruits);
echo $a."
";
echo $b."
";
echo $o."
";
?>
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