why does the And function not work here?

[kalim]

Hi excel users.

Can someone explain to me why the code below evaluates to true when it should evaluate to false. (Yes I know the second or statement is the same - Changing it does fix the problem -I fixed it in my real code), but shouldn't it still evaluate to false regardless, as the first condition is false?
'Range("e9") = 1'. Yes E9 is blank.

Sub test()
 
If Range("e9") = 1 And Range("f9") = 1 Or Range("f9") = 1 Then
   Range("e10") = "yes"
Else: Range("e10") = "no"

End If
End Sub

Thanks.

 

[kalim]

Never mind I worked it out. I forgot to add brackets. Should be...

Sub test()
 
If Range("e9") = 1 And (Range("f9") = 1 Or Range("f9")) = 1 Then
   Range("e10") = "yes"
Else: Range("e10") = "no"

End If
End Sub

 

[Rick Rothstein]

First off, And is an operator in the VB world, not a function. I think the problem you seeing has to do with operator precedence and the fact that VB does not "short-circuit" its expression evaluation (meaning it evaluates the entire expression before returning its answer). The And operator has a higher precedence than Or operator, so in this arrangement... "A And B or C", I believe the "A and B" get evaluated to either True or False and then that is Or'ed with C to produce a final evaluated Boolean value. If I am right, then that would mean if C is True, then the whole expression evaluates to True no matter what "A And B" evaluates to. Usually it is a good idea to use parentheses to group the expressions in the order you want them evaluated in.