Solved

VB Significant Digits function

Posted on 2003-11-09
8
883 Views
Last Modified: 2010-08-05
Does anyone have a visual basic function that will return a passed number with a requested number of significant digits?
For example:
X = 1.233412
Y = FixSigFigs(X,3) 'I want Y to have 3 significant digits.

Function FixSigFigs( NumberToFix as double, SigFigs as Integer)

0
Comment
Question by:kar8942
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
8 Comments
 
LVL 48

Assisted Solution

by:AlexFM
AlexFM earned 83 total points
ID: 9709953
Round Function

Returns a number rounded to a specified number of decimal places.
Round(expression [,numdecimalplaces])

Dim MyVar, pi
pi = 3.14159
MyVar = Round(pi, 2) ' MyVar contains 3.14.

0
 
LVL 86

Assisted Solution

by:Mike Tomlinson
Mike Tomlinson earned 83 total points
ID: 9709955
Public Function FixSigFigs(NumberToFix As Double, SigFigs As Integer) As Double
    Dim textNumber As String
    Dim decimalPlace As Integer
    Dim digitsToRight As Integer
   
    FixSigFigs = NumberToFix ' If no change, return original number
    textNumber = CStr(NumberToFix)
    decimalPlace = InStr(textNumber, ".")
    If decimalPlace > 0 Then
        digitsToRight = Len(textNumber) - decimalPlace
        If digitsToRight > SigFigs And SigFigs >= 0 Then
            FixSigFigs = CDbl(Left(textNumber, decimalPlace + SigFigs))
        End If
    End If
End Function
0
 
LVL 86

Expert Comment

by:Mike Tomlinson
ID: 9710584
You didn't specify as to whether you wanted rounding or not.  Use the Round() function, as AlexFM suggested, if you need rounding to occur.  Otherwise, use my function if you simply want to truncate the number to the requested number of digits.
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 6

Accepted Solution

by:
VK earned 84 total points
ID: 9714620
hello kar8942 !

That isn't a simple task in general.
Of course you can use the built in round function of vb.
But this function isn't country-independent.

Example:

? round(1.145,2)
 1,14
? round(1.245,2)
 1,25

In germany for example round(1.145,2) should be 1.15.
Therefore i wrote a user defined function:

Public Function RoundIt(Number As Variant, ByVal NumDigitsAfterDecimal As Long) As Variant
    Select Case True
        Case Not IsNumeric(Number)
            RoundIt = Number
        Case Else
            NumDigitsAfterDecimal = 10 ^ NumDigitsAfterDecimal
            RoundIt = Int(CDec(CDec(0.5) + CDec(Number) * CDec(NumDigitsAfterDecimal))) / CDec(NumDigitsAfterDecimal)
    End Select
End Function

regards

V.K.
0
 
LVL 86

Expert Comment

by:Mike Tomlinson
ID: 9872472
What did you decide to use?
0
 
LVL 48

Expert Comment

by:AlexFM
ID: 10163002
kar8942 got two ways: rounding and truncating. He should decide what he need. Without his response I think points should be splitted.
0
 

Author Comment

by:kar8942
ID: 10164264
Neither answer actually worked, but I will split the points anyway. Thanks.
0

Featured Post

[Webinar] Code, Load, and Grow

Managing multiple websites, servers, applications, and security on a daily basis? Join us for a webinar on May 25th to learn how to simplify administration and management of virtual hosts for IT admins, create a secure environment, and deploy code more effectively and frequently.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Have you ever wanted to restrict the users input in a textbox to numbers, and while doing that make sure that they can't 'cheat' by pasting in non-numeric text? Of course you can do that with code you write yourself but it's tedious and error-prone …
I was working on a PowerPoint add-in the other day and a client asked me "can you implement a feature which processes a chart when it's pasted into a slide from another deck?". It got me wondering how to hook into built-in ribbon events in Office.
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question