How can I create a user defined function in excel?

If I have a equation eg: =(A1+B1*if(t10=TRUE;1;-1)), how can I define it to
a Myfunction (A1;B1;T10)?

Use Alt+F11 to open VB Editor
Use command Insert | Module
Copy this to the newly open module sheet
Function Myfunction(x, y, z)
If z Then
multi = 1
Else
multi = -1
End If
Myfunction = x + y * multi
End Function
Return to Excel and type in any cell =Myfunction(A1,B1, T10)

But why not use
Function Myfunction(x, y, z)
If z Then
Myfunction = x + y
Else
Myfunction = x - y
End If
End Function

best wishes

--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"Martinj" <[email protected]> wrote in message
news:[email protected]...
> If I have a equation eg: =(A1+B1*if(t10=TRUE;1;-1)), how can I define it
> to
> a Myfunction (A1;B1;T10)?
>

Or what I would use:

MyFunc = x + IIf(z, y, -y)
MyFunc = x + y * IIf(z, 1, -1)

To the point, no code duplication, and easier to maintain.

It would be even more useful if VB terminated its evaluation as soon as
the result was determined.

--
Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions

In article <[email protected]>,
[email protected] says...
> Use Alt+F11 to open VB Editor
> Use command Insert | Module
> Copy this to the newly open module sheet
> Function Myfunction(x, y, z)
> If z Then
> multi = 1
> Else
> multi = -1
> End If
> Myfunction = x + y * multi
> End Function
> Return to Excel and type in any cell =Myfunction(A1,B1, T10)
>
> But why not use
> Function Myfunction(x, y, z)
> If z Then
> Myfunction = x + y
> Else
> Myfunction = x - y
> End If
> End Function
>
> best wishes
>
>

Some further comment function where made to return a value
subs don't so write subs like:

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and function

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The function will return the smallest of the 2 or three numbers or cell value's

I have never liked the IIF construct!
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"Tushar Mehta" <[email protected]> wrote in message
news:[email protected]...
> Or what I would use:
>
> MyFunc = x + IIf(z, y, -y)
> MyFunc = x + y * IIf(z, 1, -1)
>
> To the point, no code duplication, and easier to maintain.
>
> It would be even more useful if VB terminated its evaluation as soon as
> the result was determined.
>
> --
> Regards,
>
> Tushar Mehta
> www.tushar-mehta.com
> Excel, PowerPoint, and VBA add-ins, tutorials
> Custom MS Office productivity solutions
>
> In article <[email protected]>,
> [email protected] says...
>> Use Alt+F11 to open VB Editor
>> Use command Insert | Module
>> Copy this to the newly open module sheet
>> Function Myfunction(x, y, z)
>> If z Then
>> multi = 1
>> Else
>> multi = -1
>> End If
>> Myfunction = x + y * multi
>> End Function
>> Return to Excel and type in any cell =Myfunction(A1,B1, T10)
>>
>> But why not use
>> Function Myfunction(x, y, z)
>> If z Then
>> Myfunction = x + y
>> Else
>> Myfunction = x - y
>> End If
>> End Function
>>
>> best wishes
>>
>>