php using variable type checking functions to check if null

Question

Can I use functions like is_integer(), is_string(), and other like them as a reliable check to see if the variable is null? I guess what I am asking is if the variable is null with they all return false?

Well, if the variable is null you can conclude that is_string() gives you false. But if is_string() gives you false, the variable is not necessary null.... so no, you cannot use to check them whether a variable is null. — Felix Kling
– Felix Kling, Commented Apr 27, 2011 at 23:55

Ignacio Vazquez-Abrams · Accepted Answer · 2011-04-27 23:51:07Z

2

Use type comparison.

$somevar === null

answered Apr 27, 2011 at 23:51

Ignacio Vazquez-Abrams

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KingCrunch Over a year ago

Same as with is_null(): Requires the existence of the variable (isset()).

N.B. · Accepted Answer · 2011-04-27 23:55:18Z

1

You can use either is_null() or use type comparison (===). They're virtually the same, except that type comparison will be slightly faster (by slightly I mean so abysmal that it almost doesn't matter).

answered Apr 27, 2011 at 23:55

N.B.

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Comments

KingCrunch · Accepted Answer · 2011-04-27 23:52:18Z

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All of the is_*() functions tests the type of a value, thats theire main purpose. To test, if a variable is null, just test it ;)

is_null($var)

answered Apr 27, 2011 at 23:52

KingCrunch

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2 Comments

tereško Over a year ago

and keep in mind that is_null() means that it already passed isset()

KingCrunch Over a year ago

You're right, but as far as I know thats required in any case.

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