The role of php yield

This article mainly introduces the role of php yield, which has certain reference value. Now I share it with everyone. Friends in need can refer to it

function createRange($number){  
  for($i=0;$i<$number;$i++){
        yield time();
    }
}$result = createRange(10); // 这里调用上面我们创建的函数
foreach($result as $value){  
  sleep(1);  
    echo $value.&#39;<br />';
 }

1. ##first Call the

   createRange function, passing in the parameter 10, but the for value is executed once and then stops, and tells foreach that the first loop can be used value.

2. ##foreach Start pairing $result Loop, come in first sleep(1), and then start using a value given by for to perform output.

3. #foreach preparation In the second loop, before starting the second loop, it makes another request to the

   for loop.

4. The for loop is executed again and the generated timestamp is told

   foreach .

5. foreach gets the second value and outputs it. Since sleep(1) in foreach, the for loop is delayed by 1 second to generate the current time

So, during the entire code execution, there is always only one record value participating in the loop, and there is only one piece of information in the memory.

No matter how big the $number is initially passed in, since not all result sets are generated immediately, the memory is always a loop of values.

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