It is no exaggeration that knowing excel formulas can give you a career boost. From someone starting at the long list of numbers, you can become a data god who can lookup, manipulate and analyze any spreadsheet by learning few excel formulas.
So when our little excel blog hit the 5000 RSS Subscriber milestone, I celebrated the occasion by asking you to share an excel formula through twitter or comments with rest of us. And boy, what an excellent list of formula tips you have shared with us all.
Here is the complete list of entries for the twitter formula contest.
Follow the links next to contributor’s name to see the original twitter post or comment
To return the full Path+Filename of your (saved) workbook
by Dmurphy on PHD comments
To return the full Path+Filename of your (saved) workbook (and dropping the [] characters) to get, for example, C:\Data\ExcelFiles\MyWorkbook.xls: =SUBSTITUTE(SUBSTITUTE(LEFT(CELL(”filename”,$A$1), FIND(”]”,CELL(”filename”,$A$1))),”[“,””),”]“,””)
Create a Dynamic Range that Grows and Shrinks with Data
by ps62 on twitter [@ps62]
IF($A6=””,””, SUM(OFFSET(Data,$A6-1,StartDateIndex-1,1,NumCols))) – makes stuff dynamic
Find the last cell in a row
by govi on twitter [@govi]
Return last filled cell in a row: =LOOKUP(9,999E+307;A1:IV1)
Cleaning your data (Example, changing the values in a column)
by artjohnson on twitter [@artjohnson]
Excel. Cust name header in C9 and text datalist below. Formula in B9 moves name from C9 to B9. Copy down. =if(isblank(C8),c9,b8)
Extract the month from a date
by Alan on PHD comments
Probably a easier way of doing this , extracting the month from a date as text. A1 is date =TEXT(DATE(0,MONTH(a1),1),”mmmm”)
Clean your text before you lookup
by rushikul on twitter [@rushikul]
=VLOOKUP(CLEAN(TRIM(E20)),F5:G18,2,0). To make sure you are using clear text, as text is most used in vookup_value
Find if two ranges are statistically different
by nandoaires on twitter [@nandoaires]
=IF((1-(1-NORMSDIST(ABS(A1-A2)/SQRT((2*AVERAGE(A1:A2)*(1-AVERAGE(A1:A2)))/(A3))))*2)>0,95;”Different”;”Equals”)
Lookup 3 criteria and return the match
by Alan_xls on twitter [@Alan_xls]
=Index(return,Match(1,(1stRange=criteria1)*(2ndRange=criteria2)*(3rdRange=criteria3),0)) Return result where 3 values match,Array Form
Offset with Match, get data from somewhere else
by Arnab Bose on PHD comments
This formula looks up data from another sheet considering three parameters keeping into account the column A and column B with sub-components (both on another sheet) and matching them up with the heading on both sheets. =OFFSET(’Data Sheet’!$C$1,MATCH(D$2,’Data Sheet’!$A$2:$A$140,0)+MATCH($B5,’Data Sheet’!$B$2:$B$20,0)-1,MATCH(D$3,’Data Sheet’!$C$1:$J$1,0)-1)
Using SUM with multiple conditions
by ps62 on twitter [@ps62]
{=SUM(IF(shoes=”nike”,Units,0))} – array formula – two conditions
VLOOKUP but get values from the left
by bsamson on twitter [@bsamson]
VLookup to return values to the left of the lookup range: =INDEX(SearchRange,MATCH(LookupValue,LookupRange,FALSE))
Getting data from a dynamic range
by Arnab Bose on PHD comments
This formula extracts data from a dynamic data range and returns a zero value if there is an #N/A error. =IF(ISNA(HLOOKUP($A14,Data!$AB$2:$AW$9,MATCH(”P”,Data!$AB$2:$AB$2,0),0)), 0,HLOOKUP($A14,Data!$AB$2:$AW$9,MATCH(”P”,Data!$AB$2:$AB$2,0),0))
Find the difference between maximums of two ranges
by PreetAulakh on twitter [@PreetAulakh]
{=MAX(K5:M5-K4:M4)}, one step formula to determine the max of difference of two ranges! No curly brackets in excel, Cltr+Shift+Enter
Find the top 3 values of a range
by JassiAulakh on twitter [@JassiAulakh]
Large(A1:A100,{1,2,3}). Gives you 3 highest values of a range. Select three cells and enter this formulas. Then Cltr+Shift+Enter
SUMPRODUCT with multiple conditions
by Martin on PHD comments
Here’s my little contribution (previously posted 😉 Named Ranges (should be dynamic, but….) Ship $A$2:$A$8 Captain $B$2:$B$8 flights $C$2:$C$8 in F:F Summary_ship $F$2:$I$2 this 3:3 Summary_Captain $E$3:$E$6 data is in range A1:C8, and summary is in E1:I6. =SUMPRODUCT((Ship=in Summary_ship)*(Captain=this Summary_Captain)*(flights))
Get the name of the workbook
by Dmurphy on PHD comments
To return the name of the workbook only, e.g. MyWorkbook.xls: =MID(CELL(”filename”,$A$1),FIND(”[“,CELL(“filename”,$A$1))+1,FIND(“]“,CELL(”filename”,$A$1))-FIND(”[”,CELL(”filename”,$A$1))-1)
Excel Formula Fun – Should we fight… ?
by chrismelck on twitter [@chrismelck]
=IF(ISERROR(VLOOKUP(WOMD,Iraq,1,FALSE)),”Declare war”,”Declare war anyway”)
More ways to use IF and Then formula
by Olu D. on PHD comments
This formula determines the Active (=”T”) status or otherwise of Employees in an Excel spreadsheet: =IF(AC2=””,”X”,IF(AND(AC2=500000,AD2=””),”T”,IF(AND(AC2500000,AD2?”),”F”,”Pls Enter Leaving Reason!!”)))
Using INDIRECT along with VLOOKUP to make dynamic lookups
by squash86 on twitter [@squash86]
=VLOOKUP(B3, INDIRECT(B36), COLUMN()-1,FALSE) The INDIRECT returns the name of a named range that holds the data table.
Calculate the p-value of a t-statistic [Don’t ask me what it is 😛 ]
by David on PHD comments
=NORMDIST(-1*ABS((Z27-AE27)/AG27),0,1,TRUE). Calculate p-value for t-statistic based on means in Z27 and AE27 and the std err of mean in AG27.
What is on the right side of that string
by aniVy on twitter [@aniVy]
=RIGHT(A1,LEN(A1)-FIND(“-“,A1,1)) – Extracts right side string after a hyphen.
Find frequency distribution of a range of values
by Cody on PHD comments
=FREQUENCY(DY5:DY118,EU4:EU14) for creating frequency distributions. I can’t believe I went so long before discovering that there’s an easy built-in array function that does this. Constructing the distribution by hand was always a pain.
In-cell bar graph
by JohnCorp on twitter [@JohnCorp]
=REPT(“|”,A1/MAX($A$1:$A$5)*30) creates a bar graph from the data in the range a1:a5, change the font to change the look of the graph
Get the name of the current worksheet
by Dmurphy on PHD comments
To return the name fo the current worksheet, e.g. “Sheet1?: =MID(CELL(”filename”,$A$1),FIND(”]”,CELL(”filename”,$A$1))+1, LEN(CELL(”filename”,$A$1))-FIND(”]”,CELL(”filename”,$A$1)))
Excel formula fun – Usetheforce()
by _mikii on twitter [@_mikii]
=usetheforce(choke,”Moff Jerjerrod”)
UDF to calculate to royalty, I am not getting any
by chrislbs on twitter [@chrislbs]
=TieredRoyalty($R$16:$T$19,I5) @r1c1 Uses a UDF to calculate royalty on I5 based on a TierTable in R16:T19, saving nested vlookups
Find the Next Friday the 13th
by S3bast1an on twitter [@S3bast1an]
ARRAYformula – Next Friday 13th is =MIN(IF(((WEEKDAY(TODAY()+ROW(1:1000);2)=5)*(DAY(TODAY()+ROW(1:1000))=13))=1;TODAY()+ROW(1:1000)))
Split first name and last name
by Mahmut on PHD comments
=LEFT(A1,FIND(” “,A1)-1) =RIGHT(A1,LEN(A1)-FIND(” “,A1)) Split first names and last names.
IF with a VLOOKUP
by m4th1337 on twitter [@m4th1337]
=IF(VLOOKUP(C1,’Historical Data’!$A$2:$S$332,4,FALSE)>F1,”-“,IF(VLOOKUP(C1,’Historical Data’!$A$2:$S$332,4,FALSE)
And now for the winners
I wish I had more prizes to give. All the tips are truly marvelous. I have learned several cool uses of excel formulas. But alas, we have only 2 prizes in this contest.
Dashboard bundle from Bonavista Systems goes to Govi
The excel formulas 2007 book by John Walkenbach goes to DMurphy
Both the winners are randomly selected. I have already sent them an e-mail with the further instructions to claim the prizes.
Big thank you to Bonavista Systems, the contest sponsor
I would like to thank Andreas from Bonavista systems for sponsoring the dashboard bundle. Bonavista systems makes some really cool tools for excel dashboards, spark-lines and helps you make cleaner and better looking charts. Checkout their products and know more about them from their site.
Further Resources if you want to learn Excel Formulas
20 Responses to “Simulating Dice throws – the correct way to do it in excel”
You have an interesting point, but the bell curve theory is nonsense. Certainly it is not what you would want, even if it were true.
Alpha Bravo - Although not a distribution curve in the strict sense, is does reflect the actual results of throwing two physical dice.
And reflects the following . .
There is 1 way of throwing a total of 2
There are 2 ways of throwing a total of 3
There are 3 ways of throwing a total of 4
There are 4 ways of throwing a total of 5
There are 5 ways of throwing a total of 6
There are 6 ways of throwing a total of 7
There are 5 ways of throwing a total of 8
There are 4 ways of throwing a total of 9
There are 3 ways of throwing a total of 10
There are 2 ways of throwing a total of 11
There is 1 way of throwing a total of 12
@alpha bravo ... welcome... 🙂
either your comment or your dice is loaded 😉
I am afraid the distribution shown in the right graph is what you get when you throw a pair of dice in real world. As Karl already explained, it is not random behavior you see when you try to combine 2 random events (individual dice throws), but more of order due to how things work.
@Karl, thanks 🙂
When simulating a coin toss, the ROUND function you used is appropriate. However, your die simulation formula should use INT instead of ROUND:
=INT(RAND()*6)+1
Otherwise, the rounding causes half of each number's predictions to be applied to the next higher number. Also, you'd get a count for 7, which isn't possible in a die.
To illustrate, I set up 1200 trials of each formula in a worksheet and counted the results. The image here shows the table and a histogram of results:
http://peltiertech.com/WordPress/wp-content/img200808/RandonDieTrials.png
@Jon: thanks for pointing this out. You are absolutely right. INT() is what I should I have used instead of ROUND() as it reduces the possibility of having either 1 or 6 by almost half that of having other numbers.
this is such a good thing to learn, helps me a lot in my future simulations.
Btw, the actual graphs I have shown were plotted based on randbetween() and not from rand()*6, so they still hold good.
Updating the post to include your comments as it helps everyone to know this.
By the way, the distribution is not a Gaussian distribution, as Karl points out. However, when you add the simulations of many dice together (i.e., ten throws), the overall results will approximate a Gaussian distribution. If my feeble memory serves me, this is the Central Limit Theorem.
@Jon, that is right, you have to nearly throw infinite number of dice and add their face counts to get a perfect bell curve or Gaussian distribution, but as the central limit theorem suggests, our curve should roughly look like a bell curve... 🙂
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I'm afraid to say that this is a badly stated and ambiguous post, which is likely to cause errors and misunderstanding.
Aside from the initial use of round() instead of int(),.. (you've since corrected), you made several crucial mistakes by not accurately and unambiguously stating the details.
Firstly, you said:
"this little function generates a random fraction between 0 and 1"
Correctly stated this should be:
"this little function generates a random fraction F where 0 <= F < 1".
Secondly, I guess because you were a little fuzzy about the exact range of values returned by rand(), you have then been just as ambiguous in stating:
"I usually write int(rand()*12)+1 if I need a random number between 0 to 12".
(that implies 13 integers, not 12)
Your formula, does not return 13 integers between 0 to 12.
It returns 12 integers between 1 and 12 (inclusive).
-- As rand() returns a random fraction F where 0 <= F < 1, you can obviously can only get integers between 1 and 12 (inclusive) from your formula as stated above, but clearly not zero.
If you had said either:
"I usually write int(rand()*12) if I need a random number between 0 to 11 (inclusive)",
or:
"I usually write int(rand()*12)+1 if I need a random number between 1 to 12 (inclusive)"
then you would have been correct.
Unfortunately, you FAIL! -- repeat 5th grade please!
Your Fifth Grade Maths Teacher
Idk if I'm on the right forum for this or how soon one can reply, but I'm working on a test using Excel and I have a table set up to get all my answers from BUT I need to generate 10,000 answers from this one table. Every time, I try to do this I get 10,000 duplicate answers. I know there has to be some simple command I have left out or not used at all, any help would be extremely helpful! (And I already have the dice figured out lol)
Roll 4Dice with 20Sides (4D20) if the total < 20 add the sum of a rerolled 2D20. What is the average total over 10,000 turns? (Short and sweet)
Like I said when I try to simulate 10,000turns I just get "67" 10,000times -_- help please! 😀
@Justin
This is a good example to use for basic simulation
have a look at the file I have posted at:
https://rapidshare.com/files/1257689536/4_Dice.xlsx
It uses a variable size dice which you set
Has 4 Dice
Throws them 10,000 times
If Total per roll < 20 uses the sum of 2 extra dice Adds up the scores Averages the results You can read more about how it was constructed by reading this post: http://chandoo.org/wp/2010/05/06/data-tables-monte-carlo-simulations-in-excel-a-comprehensive-guide/
Oh derp, i fell for this trap too, thinking i was makeing a good dice roll simulation.. instead of just got an average of everything 😛
Noteably This dice trow simulate page is kinda important, as most roleplay dice games were hard.. i mean, a crit failure or crit hit (rolling double 1's or double 6's) in a a game for example dungeons and dragons, if you dont do the roll each induvidual dice, then theres a higher chance of scoreing a crit hit or a crit failure on attacking..
I've been working on this for awhile. So here's a few issues I've come across and solved.
#1. round() does work, but you add 0.5 as the constant, not 1.
trunc() and int() give you the same distributions as round() when you use the constant 1, so among the three functions they are all equally fair as long as you remember what you're doing when you use one rather than the other. I've proven it with a rough mathematical proof -- I say rough only because I'm not a proper mathematician.
In short, depending on the function (s is the number of sides, and R stands in for RAND() ):
round(f), where f = sR + 0.5
trunc(f), where f = sR + 1
int(f), where f = sR + 1
will all give you the same distribution, meaning that between the three functions they are fair and none favors something more than the others. However...
#2. None of the above gets you around the uneven distribution of possible outcomes of primes not found in the factorization of the base being used (base-10, since we're using decimal; and the prime factorization of 10 is 2 and 5).
With a 10-sided die, where your equation would be
=ROUND(6*RAND()+0.5)
Your distribution of possible values is even across all ten possibilities.
However, if you use the most basic die, a 6-sided die, the distributions favor some rolls over others. Let's assume your random number can only generate down to the thousandths (0.000 ? R ? 0.999). The distribution of possible outcomes of your function are:
1: 167
2: 167
3: 166
4: 167
5: 167
6: 166
So 4 and 6 are always under-represented in the distribution by 1 less than their compatriots. This is true no matter how many decimals you allow, though the distribution gets closer and closer to equal the further towards infinite decimal places you go.
This carries over to all die whose numbers of sides do not factor down to a prime factorization of some exponential values of 2 and 5.
So, then, how can we fix this one, tiny issue in a practical manner that doesn't make our heads hurt or put unnecessary strain on the computer?
Real quick addendum to the above:
Obviously when I put the equation after the example of the 10-sided die, I meant to put a 10*RAND() instead of a 6*RAND(). Oops!
Also, where I have 0.000 ? R ? 0.999, the ?'s are supposed to be less-than-or-equal-to signs but the comments didn't like that. Oh well.
How do you keep adding up the total? I would like to have a cell which keeps adding up the total sum of the two dices, even after a new number is generated in the cells when you refresh or generate new numbers.
So, how do you simulate rolling 12 dice? Do you write int(rand()*6) 12 times?
Is there a simpler way of simulating n dice in Excel?
I've run this code in VBA
Sub generate()
Application.ScreenUpdating = False
Application.Calculation = False
Dim app, i As Long
Set app = Application.WorksheetFunction
For i = 3 To 10002
Cells(i, 3).Value = i - 2
Cells(i, 4).Value = app.RandBetween(2, 12)
Cells(i, 5).Value = app.RandBetween(1, 6) + app.RandBetween(1, 6)
Next
Application.ScreenUpdating = True
Application.Calculation = True
End Sub
But I get the same distribution for both columns 4 and 5
Why ?
@Mohammed
I would expect to get the same distribution as you have effectively used the same function