What approach of functions shall I use

Question

A very basic question it is but I wanted expert advice that is why posting it here.

Here are two functions,
what is the difference between the two ? Are both of them equivalently efficient and includes best practices or Which one of them is better to use in programming.

function is_numeric($number)
{
    if(!preg_match("/^[0-9]+$/",$number))
        return false;
    return true;
}

function is_numeric($number)
{
    if(preg_match("/^[0-9]+$/",$number))
        return true;
    else
        return false;
}

Answer 1

They are equivalent - choose whichever you find to be more readable.

I personally tend to leave of any else statements on conditionals if I don't need them but this is a matter of programming style rather than a matter of either programmatic performance or correctness.

Both of these code examples are functionally identical and will perform identically.

Answer 2

Some coding standards state that the first branch should be the one that is more likely, while the else branch should cope with the more exceptional things.

But this is totally esoteric, choose whatever you want.

In my personal opinion, rather use

function is_numeric($number)
{
    return preg_match("/^[0-9]+$/",$number);
}

as preg_match returns a boolean.

Answer 3

PHP has a built in is_numeric() function: http://php.net/manual/en/function.is-numeric.php why not use that.

Answer 4

How about:

function is_numeric($number)
{
    return preg_match("/^[0-9]+$/",$number);
}

This is not going to cause a performance difference though.

Answer 5

How about:

function is_numeric($number) {
    return preg_match("/^[0-9]+$/",$number);
}

Answer 6

From a readability standpoint it's better to have positive clauses, because people are likely to miss the ! when they read the source, which leads to wrong understanding of the code and often as result: Bugs.

Steffen has a valid point. I think it depends on the size of the two code blocks. If they are more or less equal, I'd use the not negated clause in the if statement.