Question

I have checked many questions on same topic on stack overflow but still I am not able to do it. Please excuse if I am missing something very trivial.

What I need to check is …whether a variable does not contain empty(or multiple whitespaces) string ?

but when I use like $a==NULL, it will fail for 0 which is a valid string.

when I use is_null() or $a===NULL, then it will only check for "" but not if user input contain multiple white space characters like " ".

I guess may be some kind of regular expression may help here but I am not sure. Please help me.

Thanks.

Answer 1

Use trim to remove whitespace characters:

if (trim($my_str) === "") {
    // do things
}

Remember to use the identical comparison operator whenever possible to avoid truthiness issues (such as "0" acting as a false value).