LEN function (1 Viewer)

[smig]

This code scrap would cause some head scratching to a beginner:

a = 3
If a = 6 Or 3 Then

I'm scratching my head now
6 or 3 will result as 7 (Or am I wrong ?) so why checking if it's 3 ???

I really like to learn new thing, but you are only trying to confuse me more

 

[Galaxiom]

Incorrectly testing a variable in an If using that style when they intend the following is not an uncommon beginner's mistake.

If a = 3 Or a = 6 Then

Ironically it is a valid statement but the False result would be quite unexpected.

 

[smig]

If a = 6 Or 3 Then

After trying the above style once or twice I found it give me a wrong answer so I never use it again.
I never knew it is a valid statement
I can't even see what is it good for, but now that I know it is possible I'll probably find it a good use at some point

A note to Markk:
I do like using binary
for example: In one of my applications I have a groups of users. To be able to set different permissions to the groups I number them using binary numbering - 1, 2, 4, 8, 16....
This way I can give permission to groups 1 and 4 only using 5.

 

[BeeJayEff]

so 00100001 corresponds to number 65, (or is also interpreted as capital A)

The latter part of that statement is making a huge assumption. Anyone still use EBCDIC ?

 

[MarkK]

There's no EBCDIC on PCs.

smig, yeah, you can essentially pile up multiple yes/no attributes in one number. That's what Dave is talking about. Bitwise math.

 

[gemma-the-husky]

If a = 6 Or 3 Then

After trying the above style once or twice I found it give me a wrong answer so I never use it again.
I never knew it is a valid statement
I can't even see what is it good for, but now that I know it is possible I'll probably find it a good use at some point

A note to Markk:
I do like using binary
for example: In one of my applications I have a groups of users. To be able to set different permissions to the groups I number them using binary numbering - 1, 2, 4, 8, 16....
This way I can give permission to groups 1 and 4 only using 5.

No, it's not so useful. I think what galaxiom was saying is that someone could easily write

If a = b or c thinking it meant

If a=b or a=c when it actually means
If a=b or'ed with 3. A legitimate (therefore not an error) but incorrect statement .
Or it might mean if a=(b or c), again unlike to be what was intended.

 

[Galaxiom]

I think what galaxiom was saying is that someone could easily write

If a = b or c thinking it meant

If a=b or a=c when it actually means
If a=b or'ed with 3.

Exactly what I meant.

 

[smig]

I understood this is what Galaxiom meant.

I said that as my crazy mind love playing around with stupid things I'll might find this a good use at some point

I already have an idea how to use it in the exemple I gave before:

If permitedGroups = myGroup or permitedGroups

If permitedGroups is 6 and im in group 2 or 4 it will be Ok, but if im in group 1 or 8 it wont

 

[smig]

I'm trying to use this OR thing, but something is not working for me. I get True at all cases
intAppsID Or MyAppID give me 6, as expected.

Function TestAppsID()

MsgBox fnCheckReportForThisApp(2, 4)

End Function


Public Function fnCheckReportForThisApp(intAppsID As Integer, MyAppID As Integer) As Boolean
' --- This test is based on binary test
' --- Each number (intAppsID, GetAppID()) is striped to it's Binary value
' --- The test compare the binary value Byte by Byte
' --- Example: 6 or 1 = 110 or 001 will result as 111 (Not 6) = False
' --- Example: 7 or 2 = 111 or 010 will result as 111 (7) = True

fnCheckReportForThisApp = False

If intAppsID = intAppsID Or MyAppID Then
    fnCheckReportForThisApp = True
End If

End Function

but if I change into this it will work:

Public Function fnCheckReportForThisApp(intAppsID As Integer, MyAppID As Integer) As Boolean
[COLOR="Red"]Dim intORresult As Integer

intORresult = intAppsID Or MyAppID 
[/COLOR]
fnCheckReportForThisApp = False

If intAppsID = intORresult Then
    fnCheckReportForThisApp = True
End If

 

[MarkK]

Don't you want to use And, not Or? If you use And, then you can determine if an attribute is set, so if you have an enum which is a bunch of squares of two, like this . . .

Public Enum enSchoolSupplies
    enUnArmed = 0
    enUzi = 1
    enColt = 2
    enSmithWesson = 4
    enWinchester = 8
    enGlock = 16
    enGrenade = 32
End Enum

. . . then when little Billy packs his back-pack in the morning, he does it like this . . .

dim BillysSupplies as long
[COLOR="Green"]'billy is bringing an Uzi, a Colt and a Glock to school today[/COLOR]
BillysSupplies = enUzi OR enColt OR enGlock

. . . so OR has the effect of adding things together. Then, when little Billy arrives at school, his teacher might ask, "Little Billy, did you bring your daddy's Uzi to school today?" All little Billy has to do is a little bitwise math like . . .

if BillysSupplies And enUzi = enUzi Then
    Msgbox "Billy brought his daddy's Uzi to school"
end if

. . . so we use And to test a number for the presence of an attribute. If we use AND and we get the same number we're testing for, then the number is present. This way we can pile a bunch of attributes into a single number, and determine which attributes are set.

 

[smig]

In my case Billy pack one gun only.
i want to check if he brought one of the guns allowed, not if he brought a specific one


But back to my question:
why do you put -
BillysSupplies = enUzi OR enColt OR enGlock

and only after that do the check:
if BillysSupplies And enUzi = enUzi Then


why can't you ask (These ones give me a wrong result):
if (enUzi OR enColt OR enGlock) And enUzi = enUzi Then...
OR
if enUzi = (enUzi OR enColt OR enGlock) And enUzi Then...

 

[MarkK]

In my case Billy pack one gun only.
i want to check if he brought one of the guns allowed, not if he brought a specific one

If BillysSupplies > enUnArmed Then
    Debug.Print "Billy is armed."
End If

If BillysSupplies is non-zero, then billy has a gun. You don't know which gun, or how many.
And for this . . .

If (enUzi OR enColt OR enGlock) And enUzi = enUzi Then

Change to this . . .

If ((enUzi OR enColt OR enGlock) And enUzi) = enUzi Then

. . . and you should get the result you expect.

 

[MarkK]

But back to my question:
why do you put -
BillysSupplies = enUzi OR enColt OR enGlock

and only after that do the check:
if BillysSupplies And enUzi = enUzi Then

Just to show the difference between OR and AND in a practical implementation of bitwise math.

 

[smig]

I know he's having one gun only, in my case I want to check if this gun is in the allowed ones list.
The code worked OK for me.
Problem was I had to use two line of codes (I took your code here):
BillysSupplies = enUzi OR enColt OR enGlock
if BillysSupplies And enUzi = enUzi Then

Using the brackets as you suggested I can now have one line of code (again your code)
if ((enUzi OR enColt OR enGlock) And enUzi) = enUzi Then


I'm using OR for my tests and it's OK.
I was only missing the brackets now.