Why does the expression < 0 = "hello" > evaluate to 'true'?

[annelinn]

Forgive a very stupid question...

If 0 = "hello" Then
    MsgBox(1, "0 is true")
EndIf

I always understood that 0 has the boolean value of false, and strings have the boolean value of true?

[Melba23]

annelinn,

0 is a number - all variables begin with $ - so 0 = "hello" changes nothing and means nothing.

"0 is true" is a literal string, so of course the MsgBox will display it just as it would display any other obviously untrue statement such as "Tony Blair did NOT lie to get the British to go to war in Iraq". Or at least it would if you got the MsgBox syntax right.

In fact the whole code is complete garbage.

M23

[annelinn]

Ah, but my problem is in this situation, where $variable might be a string, or an integer:

If $variable = "hello" Then
   MsgBox(1, "found", "hello")
EndIf

Since AutoIt uses the same label for strings and integers ($variable), and since I can't necessarily control the data type of $variable, I would have expected that...

If $variable = "hello" Then

...would be true if $variable is the string "hello", and FALSE when $variable is the integer 0.

But clearly not.

Edited December 18, 2009 by annelinn

[spudw2k]

use == instead of =

[PsaltyDS]

The native AutoIt functions generally try to auto-retype the variables to match the function requirements. A string like "123" will be converted to an integer 123. A sting like "1.23" will be converted to a float. Non-number strings like "hello" convert to 0. Try it with Number() function. Because of this, 0 = "hello" is true because in trying to convert "hello" to a numeric, it becomes 0.

You got the right answer from spudw2k, use == vice =. See "Operators" and "Variables" in the help file.

[annelinn]

Thank you, all. I had read the Datatypes help file, but I didn't spot == in the Operators help file.

Merry Xmas!