>= and lexicographic comparison...

[TJ123]

So I am trying to compare two variables.  Both contain numeric values, but the can be negative numbers and are not always integers (so they could be -3 and 1.5, respectively)

My code looks like this

if $rank >= $minrank then
DO STUFF
EndIf

I used a msgbox to display the variables and ensure they are populated as expected.  However the code does not give the expected result and seems to consistently evaluate $rank as greater than or equal to $minrank, regardless of the values stored in the variables.

All I could find in the documentation was this:

>= Tests if the first value is greater than or equal to the second. Strings are compared lexicographically even if the contents of the string happen to be numeric.

I am not entirely sure what is meant by "Strings are compared lexicographically even if the contents of the string happen to be numeric." Could this be the cause of my problem, and what are the possible solutions?

Thanks for any advice or suggestions,

TJ.

[guinness]

Post a "proper" reproducer and mention what you expect to happen.

[Melba23]

TJ123,

 

I am not entirely sure what is meant by "Strings are compared lexicographically even if the contents of the string happen to be numeric."

Firstly, you need to understand that AutoIt does not have typed variables - depending on how the interpreter thinks you are using the variable it can change the datatype automatically, or you can change a datatype by using Number, Int, String, etc. If one of the variables in a comparison expression is a number, it is usually the case that AutoIt will convert the other variable to number type also - the sole exception being the "==" operator which forces both sides to strings. If ever you find that a comparison does not appear to be working, then variable datatype mismatch should be your first thought.

Now, in your case I strongly suspect that both of the variables are strings - which means you get them compared as strings (based on their ASCII codes) and not as numbers as can be seen in this snippet:

ConsoleWrite('"-3" >= "1.5" = ' & ("-3" >= "1.5") & @CRLF)  ; Both strings - compared as strings
ConsoleWrite('-3 >= 1.5     = ' & (-3 >= 1.5) & @CRLF)      ; Both number - compared as numbers
ConsoleWrite('-3 >= "1.5"   = ' & (-3 >= "1.5") & @CRLF)    ; Mismatch - AutoIt forces to number
ConsoleWrite('"-3" >= 1.5   = ' & ("-3" >= 1.5) & @CRLF)    ; Mismatch - AutoIt forces to number

If you ever need to do a comparison, and there is the slightest doubt as to the datatype of the variables concerned, forcing them into the required type is always a good idea:

ConsoleWrite('"-3" >= "1.5" = ' & (Number("-3") >= Number("1.5")) & @CRLF)  ; Both converted to number

Clearer now?

M23

[TJ123]

Melba23, THANK YOU, THANK YOU, THANK YOU!!!

I was having trouble getting a reproducer to work (fail?) like it was in my script.

You clearly saw my issue.  I used Number and it worked perfectly the first time.

Thanks again, very much appreciated!

TJ123

[Melba23]

TJ123,

Excellent - glad I could help.

M23

[guinness]

Sometimes AutoIt is a little too forgiving when it comes to datatypes.

[AZJIO]

TJ123

http://en.wikipedia.org/wiki/Lexicographical_order

http://en.wikipedia.org/wiki/Lexicographic_preferences

Edited July 17, 2014 by AZJIO