php判断图片格式各种方法总结

$file= "test.jpg";

$filetype= strtolower(strrchr($file,"."));

$arrtype = array(".jpeg",".bmp",".gif",".jpg");

if(!in_array($filetype,$arrtype))
{
echo '不符合格式';

exit;

}

$arr = array(
array(
'sort' => 3,
'a' => 'a',
'b' => 'b'
),
array(
'sort' => 5,
'a' => 'a',
'b' => 'b'
),
array(
'sort' => 1,
'a' => 'a',
'b' => 'b'
)
);

function array_sort($arr,$key1,$sort1='asc',$key2='',$sort2='asc'){
    if (!is_array($arr)){
        return $arr;
    }
    foreach($arr AS $key => $row){
        $temp[$key] = $row[$key1];
    }
    $sort1 = $sort1 == 'asc' ? SORT_ASC : SORT_DESC;
    if(!$key2){
        array_multisort($temp, $sort1,$arr);
    } else {
        foreach($arr AS $key => $row){
            $temp2[$key] = $row[$key2];
        }
        $sort2 = $sort2 == 'asc' ? SORT_ASC : SORT_DESC;
        array_multisort($temp, $sort1,$temp2,$sort2,$arr);
    }
    return $arr;
}

function array_sort($arr,$keys,$type='asc'){
 $keysvalue = $new_array = array();
 foreach ($arr as $k=>$v){
  $keysvalue[$k] = $v[$keys];
 }
 if($type == 'asc'){
  asort($keysvalue);
 }else{
  arsort($keysvalue);
 }
 reset($keysvalue);
 foreach ($keysvalue as $k=>$v){
  $new_array[$k] = $arr[$k];
 }
 return $new_array;
}

$array = array(
 array('name'=>'手机','brand'=>'诺基亚','price'=>1050),
 array('name'=>'笔记本电脑','brand'=>'lenovo','price'=>4300),
 array('name'=>'剃须刀','brand'=>'飞利浦','price'=>3100),
 array('name'=>'跑步机','brand'=>'三和松石','price'=>4900),
 array('name'=>'手表','brand'=>'卡西欧','price'=>960),
 array('name'=>'液晶电视','brand'=>'索尼','price'=>6299),
 array('name'=>'激光打印机','brand'=>'惠普','price'=>1200)
);

$ShoppingList = array_sort($array,'price');
print_r($ShoppingList);

<?
$step = 7;
$zerotime = strtotime('1970-01-01'); // 不一定是0!

$span = ($time - $zerotime) % ($step * 86400);
$stime = $time - $span;
$etime = $stime + ($step * 86400) - 1;

$sdate = date("Y-m-d H:i:s", $stime);
$edate = date("Y-m-d H:i:s", $etime);
?>

<?php
function Test()
{
static $count = 0;

$count++;
echo $count;
if ($count < 10) {
Test ();
}
$count--;
}
?>

<?php
function foo(){
static $int = 0; // correct
static $int = 1+2; // wrong  (as it is an expression)
static $int = sqrt(121); // wrong  (as it is an expression too)

$int++;
echo $int;
}
?>

<?php
function test_global_ref() {
global $obj;
$obj = &new stdclass;
}

function test_global_noref() {
global $obj;
$obj = new stdclass;
}

test_global_ref();
var_dump($obj);
test_global_noref();
var_dump($obj);
?>
 

NULL
object(stdClass)(0) {
}

<?php
function &get_instance_ref() {
static $obj;

echo "Static object: ";
var_dump($obj);
if (!isset($obj)) {
// 将一个引用赋值给静态变量
$obj = &new stdclass;
}
$obj->property++;
return $obj;
}

function &get_instance_noref() {
static $obj;

echo "Static object: ";
var_dump($obj);
if (!isset($obj)) {
// 将一个对象赋值给静态变量
$obj = new stdclass;
}
$obj->property++;
return $obj;
}

$obj1 = get_instance_ref();
$still_obj1 = get_instance_ref();
echo "n";
$obj2 = get_instance_noref();
$still_obj2 = get_instance_noref();
?>

Static object: NULL
Static object: NULL

Static object: NULL
Static object: object(stdClass)(1) {
  ["property"]=>
  int(1)
}