1st off I'm new to PHP. I have been using for loop,while loop,foreach loop in scripts. I wonder
//do some tasks here
//do some other tasks here
which one is better for performance?
It doesn't matter.
what's the criteria to select a loop?
If you just need to walk through all the elements of an object or array, use
foreach. Cases where you need
foreach is much more convenient because it doesn't require you to set up the counting, and can work its way through any kind of member - be it object properties or associative array elements (which a
for won't catch). It's usually best for readability.
which should be used when we loop inside another loop?
Both are fine; in your demo case,
foreach is the simplest way to go.