I reduced execution time from 5 sec to .5 sec (10 times) by simply switching to the first pattern for a loop with 900 iterations over a string $text that reaches 800K by the end.PHP uses a temporary variable for combined assign-operators (unlike Java Script), therefore the left-hand-side (target) gets evaluated last.will be assigned the nearest value (from left to right) of the first variable that has a value that isn't either null or undefined, but I've not managed to find much reference material about this technique and have seen it used a lot. I know doing something similar in PHP would result in gets returned as a result of the expression.
An exception to the usual assignment by value behaviour within PHP occurs with This page really ought to have table of assignment operators,namely, See the Arithmetic Operators page ( Same as:$a = $b $a = $a $b Addition$a -= $b $a = $a - $b Subtraction$a *= $b $a = $a * $b Multiplication$a /= $b $a = $a / $b Division$a %= $b $a = $a % $b Modulus See the String Operators page( .= $b $a = $a .
$b Concatenate See the Bitwise Operators page ( &= $b $a = $a & $b Bitwise And$a |= $b $a = $a | $b Bitwise Or$a ^= $b $a = $a ^ $b Bitwise Xor$a Using $text .= "additional text"; instead of $text = $text ."additional text"; can seriously enhance performance due to memory allocation efficiency.
The reason the assignment operator is not exclusive inside the loop is because of "scope." You've instantiated the 'value' variable as 2 outside of the while loop so when you change the value of 'value' it assigns the new value to the instantiated variable.
Your first inclination might be to think of this as "equal to". It really means that the left operand gets set to the value of the expression on the right (that is, "gets set to").
Input:$a = $b $c; Meaning:$a = ($b $c) $a; Not:$a = $a ($b $c); This can be important if the target gets modified inside the expression.$a = 0;$a = ( $a) ( $a); // yields 5 (instead of 4) Document says:"An exception to the usual assignment by value behaviour within PHP occurs with objects, which are assigned by reference in PHP 5.
Objects may be explicitly copied via the clone keyword."But it's not very accurate!
Java Script has dozens of operators, so let’s focus on the ones you’re likely to see most often. Adding the grouping operator to the previous example causes 1 100 to evaluate first.
For this example, We are using two integer variables a, Total and their values are 7 and 21.
For example: Note that the assignment copies the original variable to the new one (assignment by value), so changes to one will not affect the other.
This may also have relevance if you need to copy something like a large array inside a tight loop.