PHP中header()函数有什么用?常见header 状态

header("Content-Type: application/vnd.ms-excel; charset=UTF-8");
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Content-Type: application/force-download");
header("Content-Type: application/octet-stream");
header("Content-Type: application/download");
header("Content-Disposition: attachment;filename=".$title .".xls ");
header("Content-Transfer-Encoding: binary ");

$array=array(1,2,3,4,5);  

echo $array[count($array)-1];//计算数组长度，然后获取数组最后一个元素，如果数组中最后一个元素含有非数字键名，结果可能跟预期不符合  
//适用于键名为数字的数组  

echo '<br>';  
echo end($array);//将数组的内部指针指向最后一个单元，适用于所有数组  

rsort($array);//对数组逆向排序，如果数组中含有字母或汉字，结果可能不符合预期，最适用于数字数组
echo $array[0];

<?php
$stack = array("orange", "banana", "apple", "raspberry");
$fruit = array_pop($stack);
print_r($stack);//www.111cn.net
?>
经过此操作后，$stack 将只有 3 个单元：
Array
(
    [0] => orange
    [1] => banana
    [2] => apple
)

<?php
echo “i am a.php”;
?>

<?php
$a_code = file_get_contents(‘a.php’);
echo htmlspecialchars($a_code);//www.111cn.net
?>

$file = fopen("a.php","r");

for ( $i=0; $i<strlen($hexdata); $i+=2 )
 $bindata.=chr(hexdec(substr($hexdata,$i,2)));

$bindata='';
for ( $i=0; $i<strlen($hexdata); $i+=2 )
 $bindata.=chr(hexdec(substr($hexdata,$i,2)));

$sl = "zh-CN";
$tl = "en";
function app_out($c,$gbk){
 $data = app_get_translate($c,$sl,$tl);
 $out = str_replace($c,$data,$c);
 return app_js_out($out,$gbk);
}

$sl = "zh-CN";
$tl = "en";
function app_out($c,$gbk){
 global $sl,$tl; //将此函数体内的这两个变量定义为全局变量，以便使用开头设定的值
 $data = app_get_translate($c,$sl,$tl);
 $out = str_replace($c,$data,$c);
 return app_js_out($out,$gbk);
}

<?php
if ((condition1) || (condition2)) {
    action1;
} elseif ((condition3) && (condition4)) {
    action2;
} else {
    defaultaction;
}
?>
<?php
switch (condition) {
case 1:
    action1;
    break;

case 2:
    action2;
    break;

default:
    defaultaction;
    break;
}
?>

<?php

if (($condition1
    || $condition2)
    && $condition3
    && $condition4
) {
    //code here
}
?>

<?php

$a = $condition1 && $condition2
    ? $foo : $bar;

$b = $condition3 && $condition4
    ? $foo_man_this_is_too_long_what_should_i_do
    : $bar;
?>

<?php
$var = foo($bar, $baz, $quux);
$short         = foo($bar);
$long_variable = foo($baz);
?>

<?php
class Foo_Bar
{

    //... code goes here

}
?>

<?php
function fooFunction($arg1, $arg2 = '')
{
    if (condition) {
        statement;
    }
    return $val;
}
?>

<?php

$some_array = array(
    'foo'  => 'bar',
    'spam' => 'ham',
);
?>