for循环和if语句每隔几次

I have for loop from 1 to 6000 and I would like to execute a function every 100 times. I have only such an idea:

for($i=0;$i<=6000;$i++)
{
   if($i==100 && $i==200 ... $i==6000) do something;
}

How can I solve this problem differently?

From http://php.net/manual/en/language.operators.arithmetic.php

if ($i % 100 == 0) {
    // $i can be fully divided by 100
}

The modulo operator (%) tells you if a number divided by another number has a remainder. If the remainder is 0, you know the first number is a multiple of the second (since it divides evenly).

Just check if i is a multiple of 100:

for($i=0;$i<=6000;$i++)
{
   if($i % 100 == 0) {

   } 
} 

I agree with the answers this question has received already. However, you might want to omit the case when $i is 0. So you can check it in your for loop if you are starting from 0.

for($i=0; $i<=6000; $i++)
{
   if($i != 0 && $i % 100 == 0){
    // do something
   }
}