New features of php7: changes brought by php7

Changes brought by PHP7

1. String processing mechanism modification

Strings containing hexadecimal characters are no longer regarded as numbers, nor are they treated differently.

var_dump("0x123" == "291"); // false
var_dump(is_numeric("0x123")); // false
var_dump("0xe" + "0x1"); // 0
var_dump(substr("f00", "0x1")) // foo

2. Integer processing mechanism modification

Int64 support, unifies the integer length under different platforms, and supports strings and file uploads larger than 2GB. 64-bit PHP7 string length can exceed 2^31 bytes.

// 无效的八进制数字(包含大于7的数字)会报编译错误
$i = 0681; // 老版本php会把无效数字忽略。
// 位移负的位置会产生异常
var_dump(1 >> -1);
// 左位移超出位数则返回0
var_dump(1 << 64);// 0
 // 右位移超出会返回0或者-1
var_dump(100 >> 32);// 0 
var_dump(-100 >> 32);// -1

3. Parameter processing mechanism modification

Does not support repeated parameter naming

function func(b, c) {} ; Will report an error

The two methods func_get_arg() and func_get_args() return the current value of the parameter, not the value passed in, and the current value may be modified

So it should be noted that it is best to record it in the first line of the function, otherwise if there is any subsequent modification, it will not be the initial value passed in when read again.

function foo($x) {
$x++;
echo func_get_arg(0);
}
foo(1); //返回2

4.foreach modification

foreach() loop no longer works on array internal pointers

$arr = [1,2,3];
foreach ($arr as &$val) {
echo current($arr);// php7 全返回0
}

When looping according to the value, foreach is a copy operation of the array

$arr = [1,2,3];
foreach ($arr as $val) {
unset($arr[1]);
}var_dump($arr);

The latest php7 will still print out [1,2,3]. (ps: 7.0.0 does not work)
The old one will print out [1,3]

When looping according to the reference, modifications to the array will affect the loop

$arr = [1];
foreach ($arr as $val) {
var_dump($val);
$arr[1]=2;
}

The latest php7 will still add a cycle of new elements. (ps: 7.0.0 does not work)

5. List modification

no longer assigns values ​​in the reverse order

/ /$arr will be [1,2,3] instead of the previous [3,2,1]

list($arr[], $arr[], $arr[]) = [1,2,3];

no longer supports string splitting function

// $x = null 并且 $y = null
$str = 'xy';
list($x, $y) = $str;

Empty list() assignment is no longer allowed

list() = [123];

list() now also works for array objects

list($a, $b) = (object)new ArrayObject([0, 1]);

6 .Variable handling mechanism modification

Indirect calls to variables, properties and methods will now be parsed strictly in left-to-right order, instead of being mixed with several special cases. Condition. The table below illustrates this change in parsing order.

The order of array elements or object attributes automatically created during reference assignment is different from before

$arr = [];
$arr['a'] = &$arr['b'];$arr['b'] = 1;
// php7: ['a' => 1, 'b' => 1]
// php5: ['b' => 1, 'a' => 1]

7. Miscellaneous

1.debug_zval_dump() now prints "int" instead of "long", and prints "float" instead of "double"

2.dirname() added optional The second parameter, depth, gets the name of the parent directory one depth level up from the current directory.

3.getrusage() now supports Windows.mktime() and gmmktime() functions no longer accept the is_dst parameter.

4. The preg_replace() function no longer supports "\e" (PREG_REPLACE_EVAL). Preg_replace_callback() should be used instead.

5. The setlocale() function no longer accepts the category input string. The LC_* constants should be used.

6.exec(), system() and passthru() functions have added protection for NULL.

7.shmop_open() now returns a resource instead of an int. This resource can be passed To shmop_size(), shmop_write(), shmop_read(), shmop_close() and shmop_delete().

8. To avoid memory leaks, xml_set_object() now requires manual clearing of $parse at the end of execution.

9.curl_setopt setting item CURLOPT_SAFE_UPLOAD change

TRUE disables the @ prefix for sending files in CURLOPT_POSTFIELDS. This means @ can be safely used in fields. CURLFile can be used as an upload alternative.
Added in PHP 5.5.0, default value is FALSE. PHP 5.6.0 changes the default value to TRUE. . PHP 7 removed this option and you must use the CURLFile interface to upload files.

Recommended tutorial: "PHP7 Tutorial"

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