PHP FOR LOOP COUNTING LETTERS MANUAL
PHP FOR LOOP COUNTING LETTERS ARCHIVE

This 'discovery' was made from using an example of 16 bit crc calculation over at the 'crc32' function manual page, that do exactly that.Įcho ' Tot After: '. If the change is only occationly, You could just refresh the length variable or else just live with a quite slow loop. Note: as a real hard-core programmer You are aware, that this is only valid if you don't change the string content inside the loop (and hereby allso the length). Will benefit tremendously in speed by a short step that saves the string length once and use that in the loop. So loops like this, using 'strlen' in the for.įor ($i = 0 $i < strlen($crc) $i++).

This note should might be under the 'strlen' manual page, but there is a better chance for more paying attention here (nevertheless I have made a short note over there allso).Ī loop function that test for the string length at each iteration takes forever (possibly due to 'strlen' searches for the C-style string terminator - a binary 0 - every time. Warning about using the function 'strlen' i a for-loop: In this case we could also replace the entire loop with a map, which might make your algorithm clearer (although this won't work if calculateLoopLength() = 0):

In fact, we can simplify this even more, since '$i > 0' is equivalent to '$i' (due to type casting):įinally, we can switch to a 'pre-decrement' instead of a 'post-decrement' to be slightly more efficient (see, for example, ): each iteration is independent) then we don't need to use an extra variable either, we can just count down (ie. However, if the order the looping doesn't matter (ie. For example, let's say I have the following code:Īs other comments have pointed out, if 'calculateLoopLength' will keep giving back the same value, it can be moved outside the loop : Remember that for-loops don't always need to go 'forwards'.

PHP FOR LOOP COUNTING LETTERS ARCHIVE

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Php for loop counting letters