PHP isset () function

[kurt.santo]

I understand that the isset () function tests if a variable has a value. But I do not understand that this includes 0, false or an empty string, but not null? What is the difference between 0 and null anyhow? And how can an empty string be a value?

kurt

[DaveSawers]

Sounds like you need to use the function empty() if you're just trying to determine if a value has something useful in it, ie non zero or non empty string.

NULL effectively means that a value has never been set to anything. Setting a variable to zero or an empty string is therefore different to NULL because you deliberately set it to that value. This is an important distinction in programming. Some further explanation here: PHP: NULL - Manual

[kurt.santo]

Cheers,

Kurt