解决关于PHP“Undefined variable”变量未定义

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
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");

<?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',
);
?>

foreach($list as &$value){
  
   if(isOnline($value['uid'])){
   $value['sid'] = '1';
  
   }else{
      $value['sid'] = '0';
         }
         $value['likes']='1';
   $sql="SELECT uid,likes,flower  FROM ".DB::table("dmember_member_count")." WHERE uid='".$value['uid']."'";
   $fff = DB::query($sql);
   $ffff = DB::fetch($fff);
   //print_r($ffff);
  
   $value['flower']=$ffff['flower'];
   $value['likes']=$ffff['likes'];
  }

<?php
$a=array("Dog","Cat");
array_push($a,"Horse","Bird");
print_r($a);
?>

输出：

Array ( [0] => Dog [1] => Cat [2] => Horse [3] => Bird )

<?php
$a=array("a"=>"Dog","b"=>"Cat");
array_push($a,"Horse","Bird");
print_r($a);
?>

输出：

Array ( [a] => Dog [b] => Cat [0] => Horse [1] => Bird )