PHP之数组学习

今天学习了数组，可以说是php的数据应用中较重要的一种方式。php的数组函数众多，下面是我学习的小结，借此记之，便于以后鉴之……
　　一、数组定义：
　　数组的定义使用 array（）方式定义，可以定义空数组：

<?php
$number = array(1,3,5,7,9);
//定义空数组
$result = array();
$color =array("red","blue","green");
//自定义键值
$language = (1=>"english",3=>"chinese",5=>"franch");
//定义二维数组
$two = array(
"color"=>array("red","blue"), //用逗号结尾
"week"=>array("monday","friday") //最后一句没有标点
)；
?>

二、创建数组：
　　创建数组包含的函数有compact()、
　　　　1.compact()函数——将一个或多个变量（包含数组）转换为数组：
　　　　　　array compact ( mixed $varname [, mixed $... ] )　　

<?php
$number = "1,3,5,7,9";
$string = "i'm phper";
$array = array("and","you?");
$newarray = compact("number","string","array");
print_r ($newarray);
?>

compact()函数用于将两个或多个变量转换为数组，当然也包含数组变量。其参数是变量的名称而非带有$全名。
　　　　　　相反的函数是extract()作用顾名思义就是将数组转换为单个的字符串，键值作为其字符串名称，数组值作为字符串的值。
　　　　　　运行结果:

array ( [number] => 1,3,5,7,9 [string] => i'm phper [array] => array ( [0] => and [1] => you? ) )

2.array_combine()——将两个数组重组成一个数组,一个作键值一个做的值：
　　　　　　array array_combine ( array $keys , array $values )

<?php
$number = array("1","3","5","7","9");
$array = array("i","am","a","php","er");
$newarray = array_combine($number,$array);
print_r ($newarray);
?>

array_combine函数不多说了，谁看了都明白
　　　　　　运行结果：

array ( [1] => i [3] => am [5] => a [7] => php [9] => er )
　　　　3.range()函数——创建指定范围的数组：
　　　　　　　不多说了，直接上实例——

<?php
$array1 = range(0,100,10);//0为起始值，100为结束值，10为步进值(默认步进值为1).
print_r($array1);
echo"<br />";
$array2 = range("a","z");
print_r($array2);
echo "<br />";
$array3 = range("z","a");
print_r($array3);
?>

range()函数的默认步进值是1！
　　　　　　运行结果：

array ( [0] => 0 [1] => 10 [2] => 20 [3] => 30 [4] => 40 [5] => 50 [6] => 60 [7] => 70 [8] => 80 [9] => 90 [10] => 100 )
array ( [0] => a [1] => b [2] => c [3] => d [4] => e [5] => f [6] => g [7] => h [8] => i [9] => j [10] => k [11] => l [12] => m [13] => n [14] => o [15] => p [16] => q [17] => r [18] => s [19] => t [20] => u [21] => v [22] => w [23] => x [24] => y [25] => z )
array ( [0] => z [1] => y [2] => x [3] => w [4] => v [5] => u [6] => t [7] => s [8] => r [9] => q [10] => p [11] => o [12] => n [13] => m [14] => l [15] => k [16] => j [17] => i [18] => h [19] => g [20] => f [21] => e [22] => d [23] => c [24] => b [25] => a )

4.array_fill()函数——填充数组函数：

<?php
$array = range(1,10);
$fillarray = range("a","d");
$arrayfilled = array_fill(0,5,$fillarray);//这里的$fillarray可以是字符串，如"test".
echo "<pre>";
print_r ($arrayfilled);
echo "</pre>";
$keys = array("string","2",9,"sdk","pk");
$array2 = array_fill_keys($keys,"testing");
echo "<pre>";
print_r ($array2);
echo "</pre>";
?>

运行结果：

array
(
[0] => array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[1] => array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[2] => array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[3] => array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
[4] => array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
)
array
(
[string] => testing
[2] => testing
[9] => testing
[sdk] => testing
[pk] => testing
)

二、数组的遍历：
　　　　1.foreach遍历：
　　　　　　　foreach (array_expression as $value){}
　　　　　　　foreach (array_expression as $key => $value){}
　　　　　　闲话少说，上实例：

<?php
$speed = array(50,120,180,240,380);
foreach($speed as $keys=>$values){
echo $keys."=>".$values."<br />";
}
?>

运行结果：

0=>50
1=>120
2=>180
3=>240
4=>380

2.while循环遍历：
　　　　　　while循环遍历一般结合list函数，以下是实例

<?php
$staff = array(
array("姓名","性别","年龄"),
array("小张","男",24),
array("小王","女",25),
array("小李","男",23)
);
echo "<table border=2>";
while(list($keys,$value) = each($staff)){
list($name,$sex,$age) = $value;
echo "<tr><td>$name</td><td>$sex</td><td>$age</td></tr>";
}
echo "</table>";
?>

运行结果：

姓名	性别	年龄
小张	男	24
小王	女	25
小李	男	23

3.for循环遍历：

<?php
$speed = range(0,220,20);
for($i =0;$i<count($speed);$i++) {
echo $speed[$i]." ";
}
?>

运行结果：

0 20 40 60 80 100 120 140 160 180 200 220