php学习笔记：php中的数组
<?php#php_array.php
/*默认的方式下，php的array的key是非负整数，这种情形和多数语言如c,c++,java中的数组是一致的
*从这点看，java中的数组其实是php中数组的一种默认的方式；而php的array则还有java中Map类的特性：key－value
×php manual中的说法“PHP 中的数组实际上是一个有序图。图是一种把 values 映射到 keys 的类型”
*/
$array=array("0","1","2","3","4","5");
print_r($array);
/*
output:
Array
(
=> 0
=> 1
=> 2
=> 3
=> 4
=> 5
)
*/
//用 count() 函数来数出数组中元素的个数
for ($i=0,$size=count($array);$i<$size;$i++)
{
echo $array[$i];
echo "\n";
}
/*
output:
0
1
2
3
4
5
*/
/*use foreach to loop*/
echo "foreach to loop\n";
foreach($array as $temp){
echo($temp);
echo "\n";
}
//output as above
/* foreach example 1: value only */
$a = array (1, 2, 3, 17);
foreach ($a as $v) {
print "Current value of \$a: $v.\n";//这里使用了转义字符\，使得$a作为一个字串输出
}
/*
output:
Current value of $a: 1.
Current value of $a: 2.
Current value of $a: 3.
Current value of $a: 17.
*/
/* foreach example 2: value (with key printed for illustration) */
$a = array (1, 2, 3, 17);
$i = 0; /* for illustrative purposes only */
foreach ($a as $v) {
print "\$a[$i] => $v.\n";
$i++;
}
$array2=array("a"=>"avalue","b"=>"bvalue","c"=>"b");
print_r($array2);
echo "****\n";
echo $array2[$array2["c"]];//
//echo $array2[$array2];//企图像java那样使用数组下标方式，是无效的
echo "\n***\n";
/*output:
****
bvalue
***
*/
$arr = array("foo" => "bar", 12 => true);
echo $arr["foo"]; // bar
echo $arr; // 1
?>
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