White Spaces，Comments，Empty Lines会增加PHP的执行时间吗？ [重复]

Question

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• Commenting interpreted code and performance 9 answers

i have this doubt from many days. in every PHP code i write, i will write many comments, leave many white spaces and leave 4 to 5 empty lines between section and section (to make it clear for me)

will all these empty spaces, comments, empty lines make my PHP code to run slow ?

personal experiences are much appreciated :)

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Answer 1

This is really a matter of IO and hard drive speed. If your bare file is 10KB and comments and line breaks add 4KB then the extra time that the hard drive spends reading more KB is what you need to benchmark (it's negligible by the way), not even worth your time.

If you start getting into micro-optimization then you run the risk of making your code absolutely horrid to read and maintain.

The best way to speed up your code is to re-factor code where necessary and don't do silly things that obviously hog resources like this crude example:

<?php

$arr = array(); // pretend it has 50,000 items

//GOOD IDEA: count the array once and reference that number
$arr_count = count($arr);
for($i=0; $i < $arr_count; $i++){
    echo $arr[$i];
}


//BAD IDEA: re-counting the array for every iteration
for($i=0; $i < count($arr); $i++){
    echo $arr[$i];
}

?>

Also unsetting a large array after you are done using it is better than waiting for the Garbage Collector to kick in. For example: pulling data from DB and looping through it. Unset the data when done and keep coding.