Dummy Data – How to use the Random Functions
Using collected or known data is the best when developing Excel models, but from time to time this may not be available when you are developing your model.
This post will look at some options for setting up Dummy Data using Excels Random functions.
Variability
Real data displays a range of variability, but this variability is generally within ranges or distributions of ranges of results.
All fields type can contain variability
ie: Country, State Names and Zip/Postal Codes, Maybe large lists but are fixed
Peoples Names, Maybe a large lists but are fixed by local rules
Ages, generally less than 80, never less than 0
Dates: Rarely before 1990 or 1900 in rare cases
Lists: are fixed
Numbers: generally random or conforming to a fixed distribution or known trend
Numbers: may include integers, decimals, negatives, extremely large numbers or all combinations
In generating random lists you will need to choose if you want random data, random data within constraints or random with a distribution. The choice is really yours and should in part be based on what the data is being used for and how accurately it needs to reflect reality.
Techniques
The techniques described below are all shown with a worked example in the attached Examples File or the Excel 2003 Example
Each example is annotated below like (Example 4.). ie: Refer to Example 4 in the above example files.
Dates
Setting up Random Dates is a simple process using the Date function.
=Randbetween(StartDate,EndDate)
Dates in a Range of Years
=Randbetween(Date(2000,1,1),Date(2011,12,31))
Will give a list of Random dates between 1 Jan 2000 and 31 Dec 2011 (Example 1.)
(Thanx Mike W)
Dates in a Month
=Date(2010, 6, Randbetween(1,30)
Will give a list of Random dates between 1 June 2010 and 30 June 2010 (Example 2.)
Don’t worry that the above formula (Example 1) can actually produce a 31 Feb 2005, the Date function will happily convert that to 3 March 2005 (Example 3.)
Dates within a Date Distribution
=DATE(2011,7,NORMINV(RAND(), 0,60))
Will give a list of Random dates between approximately 1 Jan 2010 and 31 Dec 2010, with a mean of July 1 and standard deviation of 2 Months (60days) (Example 4.)
Where NORMINV(RAND(), 0,60) will return values between -180 and +180, 99.7% of the time
Text Fields
Dependant on how many items in the list you require there are 3 techniques available
Choose
For small lists of less than 6 to 10 items you can use a simple Choose function (Example 5.)
=Choose(Randbetween(1,6),”Item 1″, “Item 2”, “Item 3”, “Item 4”, “Item 5”, “Item 6”)
VLookup
Using VLookup (Example 6.)
=Vlookup(Randbetween(1,List Length), List, 2)
Index
Using Index (Example 7.)
=Index(List, Randbetween(1, Counta(List) ))
Numbers
Small Random List of Numbers
Random from a small list of numbers (Example 8.)
=Choose(Randbetween(1,6), Numb 1, Numb 2, Numb 3, Numb 4, Numb 5, Numb 6 )
Note that the numbers:
- Don’t have to be in any order,
- Can be integers, negatives or contain decimals
- Can be repeated
eg: =Choose(Randbetween(1,6), 18, 21, -19, 36.4, 18, 24)
Random Integers
Return Integers between Start and Finish (Example 9.)
=Randbetween(Start, Finish)
=Randbetween(50, 100)
Will return an Integer between 50 and 100
Random Numbers
=Rand()
Will return a random number between 0 and 1
=Round(Rand()*100, 2)
Will Return Numbers between 0 and 100 with 2 Decimal places (Example 10.)
Random Numbers Based on a Distribution
=Norminv(Rand(), Mean, SD)
Will return a random number between 0 and 1 based on a distribution of Average = Mean and Standard Deviation = SD
=Norminv(Rand(), 50, 17)
Will return a random number between 0 and 100 based on a distribution of Average = 50 and Standard Deviation = 17, (Example 11.)
Random Numbers Fitting a Trend
If your distribution has to match a trend add a Random component to the Trends equation (Example 12.)
Y=mX+c
= rand() * X + rand()*5
= rand() * A2 + rand()*5
True/False
Choose
Use Choose and Randbetween (Example 13.)
=Choose(Randbetween(1,2), True, False)
If
Use If and Rand (Example 14.)
=If(Rand()<0.5, True, False)
Combination Text and Numbers
The above techniques can be combined to make lists of Alpha Numeric Data
Say your business has a fleet of vehicles (TR=Truck, VN=Van, CAR=Car)
=Choose(Randbetween(1,3),”TR”,”VN”,”CAR”) & Text(Randbetween(1,15),”0#”)
Will randomly choose 1 of “TR”,”VN”,”CAR” and add a random number between 1 and 15 to it format with a leading 0, eg: TR05, (Example 15.)
Other Sources of Data
Random Data
There are a number of web sites where Random Data is available.
http://www.fakenamegenerator.com/order.php
http://www.generatedata.com/#generator
http://www.melissadata.com/lookups/
Open Source Data
There are a number of web sites where Open Source Data is available.
http://www.readwriteweb.com/archives/where_to_find_open_data_on_the.php
Function Used:
Rand: Returns a random number between 0 and 1.
Randbetween: Returns a random Integer between lower and upper limits. Pre Excel 2007 Randbetween was only available through installation of the Analysis Toolpak (Thanx Luke).
Norminv: Returns the inverse of the normal cumulative distribution. That is it returns the X value from a Normal Distribution that has a know Mean and Standard Deviation where the a known cumulative percentage is supplied.
Choose: Choose an item from a list of up to 254 items.
Vlookup: Lookup the matching value from a list and return a data item from another column from the same location.
Index: Retrieve an items from a defined location within a range.
Text: Displays a number as Text with a defined format.
Other Uses of Random Functions
Of course the techniques shown here don’t have to be used for setting up Dummy Data.
One area where Random numbers is used is in Monte Carlo Simulation. This has been discussed at Chandoo.org at Data Tables and Monte-Carlo Simulations in Excel a Comprehensive Guide
Techniques
The techniques described above are all shown with a worked example in the attached Examples File or the Examples File 2003 ver
Limitations in Pre Excel 2007 versions
The Excel function, Randbetween, was only introduced in Excel 2007. As such the exaples above will only work in 2007/10.
However a simple alternative is available
Randbetween(Low, High) = Low + Int(Rand()*(High-Low))+1
Randbetween(90, 100) = 90 + Int(Rand()*10)+1
Examples using this approach are shown in the 2003 Version of the Examples files above.
How have you made Dummy Data or used the Random Functions?
How have you made Dummy Data or How have you used it ?
How have you used Random Numbers in your workbooks ?
Let us know in the comments below:
20 Responses to “Untrimmable Spaces – Excel Formula”
Hi Chandoo,
First of all, HAPPY NEW YEAR!!! Wish you and your family another fruitful year ahead.
To answer your question: Power Query is the best way to trim. 🙂
Btw, if Power Query is not available, then formula would absolutely do... but did you forget to mention also Char 32?
One more question: Is the trailing minus meant to be a negative number? Maybe only the sender knows... 🙂
Cheers,
I just see your PQ way, it is amazing, I think it is the most simple way.
No idea how it did it?
I know these spaces can be a real pain but these days I advise Excel users to learn and use Flash Fill and that will learn what to do pretty quickly.
Highlight range to be cleaned. Then, in Replace, hold down the Alt key and type 0160. Replace with nothing.
I accomplished this by writing a macro to go through all the possible unprintable characters. Looped through the range.
@Steve
Brute force works just as well, its just slower
I use a different method here. First, I will copy the data from Excel and paste it in a notepad. In Notepad, I will do a Find Blanks (Space " ") and Replace (Empty) with nothing.
Then you can copy the data from Notepad and paste it back to Excel which will be a perfect number as you desire.
But Thanks for the formula. Its probably the 2nd out of 8 tricks as Chandoo mentioned. Waiting for the rest among 8 from other users 🙂
Hi....
You don't always need notepad for that. I use the Find/Replace is Excel works just fine.
I don't understand the x's. Why weren't they removed in the formula? Or are they part of some sort of numeric formatting that I'm not familiar with? I saw how you handled the non-breaking spaces and the dashes, but am confused about what role the x's played in all this.
Thanks!
Hi Andrew ,
The xs have been used solely to demarcate the actual data text ; thus , without the x in place at the end of text , as in :
x 4,124,500.00 x
it would be impossible to know that there are unwanted trailing characters , in this case , after the last 0.
These xs are not part of the original data text , nor are they used in the formulae ; they are put in only so that readers can visualize the individual items of data as they are in practice. Think of them as imaginary delimiters.
Oh, that makes sense! Thank you for the explanation. I had a feeling it was something along those lines.
You can type this character using the Keys Alt+0160.
Very useful to replace this Character using Find and Select resource.
For many years, my jobs have included ETL tasks and I built this macro to help long, long ago. I tweak it every now and again. Many co-workers, past and present, have it wired to a button on their toolbar.
Sub Clean_and_Trim()
'CAUTION: Strips leading zeroes -- do not use on zipcodes, etc.
If Application.Calculation = xlCalculationAutomatic Then
Application.Calculation = xlCalculationManual
Revert = 1
ElseIf Application.Calculation = xlCalculationManual Then
Revert = 0
End If
For Each Cell In Selection
For x = Len(Cell.Value) To 1 Step -1
If Asc(Mid(Cell.Value, x, 1)) = 160 Then
Cell.Replace What:=Chr(160), Replacement:=" ", LookAt:=xlPart, MatchCase:=True
End If
If Asc(Mid(Cell.Value, x, 1)) = 32 Then
Cell.Replace What:=Chr(32), Replacement:=" ", LookAt:=xlPart, MatchCase:=True
End If
Next x
If Cell.Value "" Then
Cell.Value = Application.Clean(Application.Trim(Cell.Value))
End If
Next
If Revert = 1 Then
Application.Calculation = xlCalculationAutomatic
ElseIf Revert = 0 Then
Application.Calculation = xlCalculationManual
End If
End Sub
This is awesome! What if you have several characters you need to have removed? What would be the easiest way as I can imagine there are several ways.?
# - 35
$ - 36
- 62
/ - 47
, - 44
. - 46
" - 34
: - 58
This is typical case of a Fitbit data export to Csv file. Each number has CHAR160 as thousand separator.. how smart Fitbit, thank you 😉
By the way, i prefer to copy the character, and use find and replace.
Sometimes it happens if you copy a table from outlook and paste it in excel. When you apply formula on those cells you will get error. What i use to do is
copy one character that looks like space,
select the entire range,
go to Find and replace,
Paste the copied character in Find option
Leave the replace option unfilled..
click on replace all..
All the errors shall be converted in to proper values..
Process looks lengthier.. but it is one of the simplest method
If Clean, Trim, and Substitute, or Find and Replace does not complete the job, I usually enter a value of 1 in an empty cell. Copy the Value of 1, Highlight the range of text numbers, and Paste Special, Values, Multiply. This site is great!
You can use Dose for Excel Add-In that can quickly clean huge data with one click besides more than +100 new functions and features to add to your Excel to save time and effort.
https://www.zbrainsoft.com
Hi,
I have a problem in excel. The sheet attached herewith.
TABLE CONFIG 2/6
A B C D E F G H
1 WEIGHT1 43,599 WEIGH2 62500 WEIGHT3 77000 WEIGHT4 66,500
2 DEDUCTION1 15,000 DEDUCTION1 15,000 TEMP 0 DEDUCTION2 11,005
3 RESULT 58,599 RESULT-1 77,500 RESULT-2 77,000 RESULT-3 77,505
4 RESULT SUBSTRACT 0 0 0
5 REQUIRED VALUE 77,500 77,000 77,505
Note: 1- RESULT (58599) IS TO BE DEDUCTION EITHER FROM D4 OR F4 OR H4 WHICHEVER IS MOST
LEAST CELL AMONG RESULT-1 OR RESULT-2 OR RESULT 3.
2-HENCE, RESULT VALUE $B$3 IS TO BE PRESENTED ON CELL EITHER D4 OR F4 OR H4 WHICHER IS
MOST LEAST VALUE
3-FORMULA =IF(E8<H8,$B$9,IF(E8<J8,$B$9,IF(H8<J8,$B$9,IF(H8<E8,$B$9,IF(J8<H8,$B$9))))))
CREATED ON CELL D4,F4 & H4 DID NOT WORK.
PLS FOR YOUR HELP.
THANK YOU
@R
Why not ask the question in the Chandoo.org Forums
https://chandoo.org/forum/
You can attach a file there