PHP7.1的几个新特性

#以前多个变量赋值你可以这样写
$a = 1;
$b = 2;
$c = 4;
#或者相同值的你可以这样写 
$a = $b = $c = [];
#现在你可以这样为不同值的多个变量赋值
[$a, $b, $c] = [1, 2, 3];
`#以前用mcrypt写一个加密大概是这样
public function encryptData($str, $key)
{
    $block = mcrypt_get_block_size('des', 'ecb');
    $pad = $block - (strlen($str) % $block);
    $str .= str_repeat(chr($pad), $pad);
    $res = mcrypt_encrypt(MCRYPT_DES, $key, $str, MCRYPT_MODE_ECB);
    return strtoupper(bin2hex($res));
}
#现在你需要用openssl来替换了
public function encryptData($str, $key)
{
    $res = openssl_encrypt($str, 'DES-ECB', $key, OPENSSL_RAW_DATA);
    return strtoupper(bin2hex($res));
}
#以前用mcrypt写一个解密大概是这样
public function decryptData($str, $key)
{
    $str = strtolower($str);
    $str = pack('H*', $str);
    $decrypted = mcrypt_decrypt(MCRYPT_DES, $key, $str, MCRYPT_MODE_ECB);
    $dec_s = strlen($decrypted);
    $padding = ord($decrypted[$dec_s - 1]);
    $decrypted = substr($decrypted, 0, -$padding);
    return $decrypted;
}
#现在也要用openssl替换了
public function decryptData($str, $key)
{
    $str = strtolower($str);
    $str = pack('H*', $str);
    $decrypted = openssl_decrypt($str,'DES-ECB', $key,OPENSSL_RAW_DATA);
    return $decrypted;
}`
`# 以前可以这样
$num = 1 + 'abc323vccc';    //result 1;
$num = 1 +'100abc';    //result 101;
#现在你不能那样写了，将会得到这样的一个警告
PHP warning:  A non-numeric value encountered on line 1```