When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).
I conducted many tests (I believe to be fair), and here's one of the results:
$i++ took 8.47515535355 seconds and 2360 bytes
++$i took 7.80081486702 seconds and 2160 bytes
Here's my code. If anyone sees a bias in it, tell me. I conducted it many times, each time going through a loop one million iterations and doing each test 10 - 15 times (10 - 15 million uses of the ++ operator).
ini_set( 'MAX_EXEC_TIME', 120 );
ob_start( );
$num_tests = 10;
$startFirst = $startSecond = $endFirst = $endSecond = $startFirstMemory = $endFirstMemory = $startSecondMemory = $endSecondMemory = $someVal = 0;
$times = array( '$i++' => array( 'time' => 0, 'memory' => 0 ), '++$i' => array( 'total' => 0, 'memory' => 0 ) );
for( $j = 0; $j < $num_tests; ++$j )
{
for( $i = 0, $startFirstMemory = memory_get_usage( ), $startFirst = microtime( true ); $i < 10000000; $i++ ){ $someval = 2; }
$endFirstMemory = memory_get_usage( );
$endFirst = microtime( true );
________số 8 $times[ '$i++' ][ $j ] = array( 'startTime' => $startFirst, 'endTime' => $endFirst, 'startMemory' => $startFirstMemory, 'endMemory' => $endFirstMemory );
$times[ '++$i' ][ $j ] = array( 'startTime' => $startSecond, 'endTime' => $endSecond, 'startMemory' => $startSecondMemory, 'endMemory' => $endSecondMemory );
}
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).0
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:1
I conducted many tests (I believe to be fair), and here's one of the results:2
I conducted many tests (I believe to be fair), and here's one of the results:3
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).5
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).6
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).7
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).8
PHP was cung cấp một số trình lặp trong nhiều nhiệm vụ hàng ngày. View SPL Iterators for a list Ví dụVí dụ số 1 sử dụng cơ bản Ví dụ này chứng minh rằng các phương thức đặt hàng được gọi khi sử dụng foreach với một trình lặp When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).9
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:1Ví dụ trên sẽ xuất ra một cái gì đó tương tự như string(18) "myIterator::rewind"
string(17) "myIterator::valid"
string(19) "myIterator::current"
string(15) "myIterator::key"
int(0)
string(12) "firstelement"
string(16) "myIterator::next"
string(17) "myIterator::valid"
string(19) "myIterator::current"
string(15) "myIterator::key"
int(1)
string(13) "secondelement"
string(16) "myIterator::next"
string(17) "myIterator::valid"
string(19) "myIterator::current"
string(15) "myIterator::key"
int(2)
string(11) "lastelement"
string(16) "myIterator::next"
string(17) "myIterator::valid"
lục mục- Trình lặp. hiện tại - trả về phần tử hiện tại
- Trình lặp. key - Return key of the current element
- Trình lặp. Tiếp theo - Chuyển tiếp đến phần tử tiếp theo
- Trình lặp. tua lại - tua lại trình lặp lại phần đầu tiên
- Trình lặp. hợp lệ - kiểm tra xem vị trí hiện tại có hợp lệ không
Robert_e_lee tại Dell Dot Com ¶ ¶ 12 năm trước I conducted many tests (I believe to be fair), and here's one of the results:2
I conducted many tests (I believe to be fair), and here's one of the results:3
I conducted many tests (I believe to be fair), and here's one of the results:4
I conducted many tests (I believe to be fair), and here's one of the results:5
I conducted many tests (I believe to be fair), and here's one of the results:6
I conducted many tests (I believe to be fair), and here's one of the results:7Rocketinabog tại Techno-Monks Dot Net ¶ 13 năm trước When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).90
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).91
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).92fetidfrog tại gmail dot com ¶ ¶ 10 năm trước When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).93
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).94
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).95
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).96Mike Dot Thornton tại Firstroi Dot Com ¶ ¶ 13 năm trước When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).97
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).98
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).99
I conducted many tests (I believe to be fair), and here's one of the results:00
I conducted many tests (I believe to be fair), and here's one of the results:01
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).96fetidfrog tại gmail dot com ¶ ¶ 13 năm trước I conducted many tests (I believe to be fair), and here's one of the results:03
I conducted many tests (I believe to be fair), and here's one of the results:04
I conducted many tests (I believe to be fair), and here's one of the results:05
I conducted many tests (I believe to be fair), and here's one of the results:06fetidfrog tại gmail dot com ¶ ¶ 10 năm trước I conducted many tests (I believe to be fair), and here's one of the results:07
Mike Dot Thornton tại Firstroi Dot Com ¶ ¶ Geoffrey Sneddon ¶ I conducted many tests (I believe to be fair), and here's one of the results:08
I conducted many tests (I believe to be fair), and here's one of the results:09
I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:120I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:121I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:122When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).96Gilles a ¶ ¶ 8 năm trước I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:22
tua lại(). void {
var_dump(__METHOD__);
$this->vị trí = 0;
}#[ReturnTypeWillChange]
hàm công khai current() {
var_dump(__METHOD__);
return $this->mảng[$this->vị trí];
}#[ReturnTypeWillChange]
chức năng công khai key() {
var_dump(__METHOD__);
return $this->vị trí;
}chức năng công cộng tiếp theo(). void {
var_dump(__METHOD__);
++$this->vị trí;
}chức năng công cộng hợp lệ(). bool {
var_dump(__METHOD__);
return isset($this->mảng[$this->vị trí]);
}
}$it = new myIterator;cho mỗi( $it as $key => $value) {
var_dump($key, $value);
echo "\n";
}
?>4I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:125When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).96Ẩn danh ¶ ¶ 13 năm trước I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:127I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:128I conducted many tests (I believe to be fair), and here's one of the results:10
I conducted many tests (I believe to be fair), and here's one of the results:0
I conducted many tests (I believe to be fair), and here's one of the results:129I conducted many tests (I believe to be fair), and here's one of the results:20fetidfrog tại gmail dot com ¶ ¶ 10 năm trước I conducted many tests (I believe to be fair), and here's one of the results:21
I conducted many tests (I believe to be fair), and here's one of the results:22
I conducted many tests (I believe to be fair), and here's one of the results:23
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).96Mike Dot Thornton tại Firstroi Dot Com ¶ ¶ Geoffrey Sneddon ¶ I conducted many tests (I believe to be fair), and here's one of the results:25
I conducted many tests (I believe to be fair), and here's one of the results:26
I conducted many tests (I believe to be fair), and here's one of the results:27
I conducted many tests (I believe to be fair), and here's one of the results:28
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).96Gilles a ¶ ¶ 8 năm trước I conducted many tests (I believe to be fair), and here's one of the results:30
I conducted many tests (I believe to be fair), and here's one of the results:31
I conducted many tests (I believe to be fair), and here's one of the results:32
I conducted many tests (I believe to be fair), and here's one of the results:33
I conducted many tests (I believe to be fair), and here's one of the results:34
I conducted many tests (I believe to be fair), and here's one of the results:35
I conducted many tests (I believe to be fair), and here's one of the results:36
I conducted many tests (I believe to be fair), and here's one of the results:37
I conducted many tests (I believe to be fair), and here's one of the results:38
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).96Ẩn danh ¶ ¶ Geoffrey Sneddon ¶ I conducted many tests (I believe to be fair), and here's one of the results:40
Gilles a ¶ ¶ 8 năm trước I conducted many tests (I believe to be fair), and here's one of the results:41
Ẩn danh ¶ ¶ 8 năm trước I conducted many tests (I believe to be fair), and here's one of the results:42
I conducted many tests (I believe to be fair), and here's one of the results:43
I conducted many tests (I believe to be fair), and here's one of the results:44Ẩn danh ¶ ¶ 8 năm trước I conducted many tests (I believe to be fair), and here's one of the results:45
I conducted many tests (I believe to be fair), and here's one of the results:46
I conducted many tests (I believe to be fair), and here's one of the results:47
I conducted many tests (I believe to be fair), and here's one of the results:48
I conducted many tests (I believe to be fair), and here's one of the results:49
I conducted many tests (I believe to be fair), and here's one of the results:50Ẩn danh ¶ ¶ 6 năm trước I conducted many tests (I believe to be fair), and here's one of the results:51
geompse tại gmail dot com ¶ ¶ 11 năm trước I conducted many tests (I believe to be fair), and here's one of the results:52
I conducted many tests (I believe to be fair), and here's one of the results:53
I conducted many tests (I believe to be fair), and here's one of the results:54
When using the ++ operator by itself on a variable, ++$var is faster than $var++ and uses slightly less memory (in my experiments). It would seem like this could be optimized in the language during runtime (if $var++ is the only thing in the whole statement, it could be treated as ++$var).91
I conducted many tests (I believe to be fair), and here's one of the results:56Chức năng Iterator là gì?Trong JavaScript, một chu trình lặp là một đối tượng xác định một chuỗi và có khả năng là giá trị trả về khi chấm dứt. Cụ thể, một trình lặp là bất kỳ đối tượng nào thực hiện trình lặp giao thức bằng cách có một phương thức tiếp theo () trả về một đối tượng có hai thuộc tính. value. Next value in the loop. đối tượng xác định trình tự và có khả năng là giá trị trả về khi kết thúc trình tự . Cụ thể, iterator là bất kỳ đối tượng nào thực hiện giao thức Iterator bằng cách có phương thức next() trả về một đối tượng có hai thuộc tính. giá trị. Giá trị tiếp theo trong chuỗi lặp. Một người lặp lại là gì và tại sao iterator là cần thiết?Trình lặp là một đối tượng (giống như con trỏ chuột) trỏ đến một phần tử bên trong thùng chứa. Chúng ta có thể sử dụng trình lặp để chuyển nội dung của vùng chứa. Chúng ta có thể hình dung như một cái gì đó tương tự như một con trỏ trỏ đến một số vị trí và chúng ta có thể truy cập nội dung tại vị trí cụ thể đó bằng cách sử dụng chúng. một đối tượng (như con trỏ) trỏ đến phần tử bên trong vùng chứa . Chúng ta có thể sử dụng các trình vòng lặp để di chuyển qua nội dung của vùng chứa. Chúng có thể được hình dung như một cái gì đó tương tự như một con trỏ trỏ đến một số vị trí và chúng ta có thể truy cập nội dung tại vị trí cụ thể đó bằng cách sử dụng chúng. Trình PHP quan trọng như thế nào trong một ứng dụng?Trình phát triển vọng bạn xử lý dữ liệu lặp lại, thay vì đệm nó trong bộ nhớ. Mặc dù có thể làm điều này mà không cần đến tererators, nhưng sự lãng phí mà họ cung cấp che giấu việc thực hiện giúp họ thực sự dễ sử dụng. khuyến khích bạn xử lý dữ liệu theo cách lặp lại, thay vì lưu vào bộ nhớ đệm . Mặc dù có thể thực hiện điều này mà không cần trình vòng lặp, nhưng phần trừu tượng mà chúng cung cấp che giấu việc triển khai khiến chúng thực sự dễ sử dụng. Có thể lặp lại một mảng không?Các đối tượng có thể hiểu được là một khái niệm của các mảng. Đó là một khái niệm cho phép chúng tôi tạo ra bất kỳ đối tượng nào có thể sử dụng được trong vòng lặp cho. của. Tất nhiên, mảng là điều đó | 
