Formula Forensics-No. 036: Calculating Costs that Vary by Year and Age

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Van Gysel asked in a recent post at Chandoo.org for a way to calculate the costs of running a plantation.  The twist is that the costs vary by year, and based on the age of the trees.

The following is a slightly simplified version of the solution I offered:

=SUM(IFERROR(LOOKUP(“Year”&MMULT(N($B$3:B$7>0),TRANSPOSE(COLUMN($B$3:B$7)^0)), $B$11:$I$11, $B12:$I12),0)*B$3:B$7)      Ctrl+Shift+Enter

Today I am going to try and explain how the formula works.

As always at Formula Forensics, you can follow along with a sample file: Download Here

 

The Problem

In a plantation, the costs for planting and maintaining trees vary based on the age of the trees and by year.  The table below shows the acres of trees planted per year and the yield and costs per year that vary based on the age of the trees.

FF36-02

Let us look at the calculations needed for each year.

Year 2013

  • 300 acres of trees were planted in 2013.  Calculations for 2013 are as follows.  (Only Yield calculation is shown, but the process is similar for Nursery costs, Fertilizers, etc.)
  • The trees do not yield any fruits in the first year.  As such, Yield for year1=300*0=0

That was easy!

 Year 2014

  • 700 additional acres of trees will be planted in 2014.  Calculations for 2014 are as follows.  (Again, only Yield calculation is shown, but others are calculated similarly.)

FF36-Year2Calc

  • 300 acres of trees are 2 years old.  700 acres are 1 year old.
  • The 300 acres from 2013 now yield fruit since it is year2.  However, the new trees (700 acres) do not yield any fruits yet.  So total yield for 2014=300*Year2Yield+700*Year1Yield=300*5+700*0

Year 2015

  • 1000 additional acres are to be planted in 2015.  Calculations for 2015 are as follows:

FF36-Year3Calc

  • 300 acres are from 2013 (3 years old); 700 acres are from 2014 (2 years old); 1000 acres are from 2015 (1 year old).
  • Yield for 2015=300*Year3Yield + 700*Year2Yield + 1000*Year1Yield = 300*10 + 700*5 + 1000*0

 Year 2016

  • 1000 additional acres are to be planted in 2016.  Calculations for 2016 are as follows:

FF36-Year4Calc

  • Yield for 2016=300*15+700*10+1000*5+1000*0

How do we simulate the above calculation in an Excel formula?

A Solution

Let us first look at how we performed the calculations above manually, using the 2016 Yield as an example.

  1. We took each acreage value in 2016, and determined its age by counting how many years it has been since that acreage was planted.  You might have observed that the age can be counted by the number of times a value has been repeated up to that point.  (In other words, if I planted 300 acres in 2013, I should see that same amount in 2014, 2015 and 2016.) As such, 300 acres is repeated 4 times.  700 acres is repeated 3 times.  1000 acres is repeated 2 times. And the latest planting of 1000 acres exists only once.
  2. Once we determine the age for a given acreage, we looked up the yield for that age in the second table
  3. We then multiplied the acreage with the corresponding yield value.

Calculation #1 can be expressed as follows:

  • Age for acreage 1 (first planted in 2013)=count of B3:E3 where value is greater than zero.  i.e. COUNTIF(B3:E3,”>0”)
  • Age for acreage 2 (planted in 2014)=count of B4:E4 where value is greater than zero.  i.e. COUNTIF(B4:E4,”>0”)
  • Age for acreage 3 (planted in 2015)=count of B5:E5 where value is greater than zero.  i.e. COUNTIF(B5:E5,”>0”)
  • Age for acreage 4 (planted in 2016)=count of B6:E6 where value is greater than zero.  i.e. COUNTIF(B6:E6,”>0”)
  • Age for acreage 5 is zero since nothing has been planted for 2017 yet in 2016

The above approach would work if we were calculating the age one row at a time.  However, that can become tedious really fast.  We need to perform the calculation for the full range (B3:E7) together, but return the counts for each row individually.

Excel’s MMULT function comes to the rescue!

MMULT (which stands for Matrix Multiply) multiplies two matrices and returns a third matrix based on rules for matrix multiplication.  I am planning to devote a whole article to explain the MMULT function.  As such, for this article, we will summarize the utility of the function as “take a 2-dimensional array, add each column’s value for each row, and return a 1-column array”.

MMULT requires that its arguments be numeric.

So to obtain the counts for the year 2016, we can use the following:

MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0))

As you can see from the picture below, MMULT’s results are the addition of each column for each row.

FF36-TRUE FALSE to1s 0s

In the above formula, you may have noticed that the range uses absolute and relative referencing (signified by the $ sign or lack thereof).  This is to ensure that the range grows or shrinks as needed.  The upper left address is held constant ($B$3).  However, the lower right address for the range has columns that vary but row that is fixed on row #7.  This ensures that the formula would work if we copy to the left, right, etc. in the final results.

Now that we have the age for each acreage value, we can look up the corresponding yield value using (what else?) LOOKUP function.

But before we can use LOOKUP, we will need to convert the numeric values returned from MMULT into the strings Year1, Year2, etc. found in the Costs table.  Of course, you know how to do that… concatenate the string “Year” to the result from MMULT

“Year”&MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0))

For the 2016 example, we get {“Year4″;”Year3″;”Year2″;”Year1″;”Year0”}

We can now use LOOKUP as follows:

LOOKUP(“Year”&MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0)), $B$11:$I$11, $B12:$I12)

FF36-2016 calc

You may recall that LOOKUP looks up a value in the array indicated by the second argument, and returns the corresponding value from the third array argument.  In this case, instead of looking up a single value, we look up an array of values (supplied in the first argument) to the function.

The above formula translates to the following:

LOOKUP({“Year4″;”Year3″;”Year2″;”Year1″;”Year0”}, {“Year1″,”Year2″,”Year3″,”Year4″,”Year5″,”Year6″,”Year7″,”Year8”}, {0,5,10,15,20,25,30,35})

The result from LOOKUP is {15;10;5;0;#N/A}

(The last value is #N/A because there is no acreage value for 2017 yet (as of 2016 column).  The concatenation resulted in Year0 which does not exist in the “Age of The Trees” range (B11:I11) above.)

By using IFERROR(LOOKUP(…),0) we get {15;10;5;0;0}

We can now multiply the above result with the acreage values for 2016 to get {4500;7000;5000;0;0}

Finally, we SUM the values to get 16500

FF36-Final Calc

Putting it all together, we get the following formula (shown for Production for year 2016)

=SUM(IFERROR(LOOKUP(“Year”&MMULT(N($B$3:E$7>0),TRANSPOSE(COLUMN($B$3:E$7)^0)), $B$11:$I$11, $B12:$I12),0)*E$3:E$7)

One of the benefits of the above formula is that you can copy the same formula to calculate values for additional years, as well as other plantation costs.

Download

You can download a copy of the above file and follow along: Download sample file.

 

Let me know (using the comments below) what you think of the above approach and solution, as well as any other approaches you have utilized to solve a similar problem.  In the meantime, I wish you continued Excellence!

-Sajan.

 

 Other Posts in this Series

The Formula Forensics Series contains a wealth of useful solutions and information.

Visit the Formula Forensics Home Page to read other articles in this series.

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37 Responses to “Quickly Change Formulas Using Find / Replace”

  1. Andras Ujszaszy says:

    Chandoo,
    this is a really cool stuff what I use quite often. In addtion this method also could be a good choice to switch the reference type of the formulas from relative to absolute or vice versa. (just simply replace the $ in the same way).
    Andras

    • Chandoo says:

      @Andras: you are right, we can use find / replace to change references, reference types etc. Now, only if they had regex in find/ replace, we could so much more 🙂

      @Tony Rose: Thank you. This is very useful and powerful feature. I even use it for cleaning up data. While formulas are good, they are not the solution for every problem. Often when I need more powerful cleanup / changing, I copy paste the stuff to text editors like notepad++ and then use their find/replace to do the dirty task.

      • Sonia says:

        What if i have to change the formula from ='Analysis'!C1 to 'Analysis 1'!C1?
        I tried doing it using Find /Replace but could't. Encountered some errors.

        And is there a way to change this using VBA???

        • Ollie says:

          Hi,

          Did you ever get a reply to this?

          Thanks

          Ollie

        • MF says:

          to make your life easier, suggest you to avoid (Space) in worksheet names whenever possible. Consider (underscore) instead.

          • Luke Moraga says:

            As the first formula wouldn't have the single apostrophes (since there's no space) need to include that in replace. So, search for:
            Analysis

            and replace with:
            'Analysis 1'

  2. Tony Rose says:

    This could be the most useful tips I've seen in a while. I use this all the time and can instantly change 400 formulas with a few clicks. Like so many other functions in Excel, I don't know what I would do without this one.

    Keep 'em coming!

  3. [...] on formulas: 5 areas where mouse kicks keyboard’s butt | Edit formulas in bulk using Find / Replace | Excel Formulas Online [...]

  4. purushoth says:

    THANKS BRO

  5. The Red Ranger says:

    You, sir, are a god among men...

  6. David says:

    This is really cool. Your just save me hours of work. Thanks.

  7. Jodie says:

    Thanks so much for this fix! It saved me tons of work. I'm muddling my way through and this really helped!

  8. Jesse says:

    Oh... My... God!
    This tip just saved me about 2 hours every month! I can't believe how easy it is to use. Now, can somebody tell me who I should call to get a refund for the previous 100 hours I spent manually changing formulas cell by cell?
    Thanks so much! 

  9. Bilal says:

    THANK YOU!!!!
    You saved me hours, I had a sheet that has more than 500 formulas, and i needed to replace the year in all of them, you saved me hours

  10. Elliot says:

    Awesome info on replacing cell addresses in formulas. I have never heard about Ctrl+` before. Thank you!

  11. T says:

    I have something inside a formula like:
    =sum(A1, A2*10) all over I now need to get rid of the *10 {=sume(A1, A2)} I thought to use the find replace trick above but with a blank in the replace but it then outputs just zeros. I thought I could trick it by doing *1 but then it just turns into =*1) with none of my references. Does anyone have an idea how to do this?
    The Ctrl+ trick is cool.

  12. Peter says:

    Thank you! This literally will save me hours and hours of time, and that's without losing my sanity in the process!

  13. Brigitte says:

    I have Sheet(1), Sheet(2), Sheet(3), etc ... Sheet(100).
    Then there's a summary tab where I want to recap information on all those different sheets. Is there anyway to create a formula on the Summary tab to get ='Sheet(1)'!B$29 copied down for all 100 sheets without having to change each sheet # within the formula by hand?

    • Hui... says:

      @Brigitte
      If you have a list of the sheet names in A2:A100
      In B2: =INDIRECT("'"&A2&"'!$B$29")
      Copy down

      or if you don't have a list of the sheets names you can make it up on the fly
      =INDIRECT("'sheet("&ROW()-1&")'!$B$29")
      Copy down

      • Brigitte says:

        Thanks for the suggestion. However, I copied your formula right back to my file and it didn't work. So I did it another way. I put the tab/cell reference in one cell and then did an =INDIRECT() to capture that information.

        K2="'Sheet("&L2&")'!B$29" which has a value of 'Sheet(1)'!B$29
        B2=INDIRECT(K2) which now has a value of 40 (contents on Sheet(1).

        Thank you!!!!

  14. Mohammed Ali says:

    Thank you ..

  15. Niharika says:

    Hi, Out of all the formulae, I wish to replace the formula which has generated 0 value with blank space? I am unable to do it with find and replace function,

    Please suggest.

  16. Rashed says:

    Thanks.

  17. Kevin says:

    Chandoo, you literally just saved me about 2 hours of work. I had a document with a daily report in two formats. The second formate just linked to all the appropriate cells in the other format (different sheets). This was 180 references that needed to be changed and I had to make this for a 4 week period (aka 28 different sheets at 180 references to change per sheet).

    Thanks so much.

  18. Brian says:

    I have tried this way and without using the Ctrl-` formula view
    Either way, I am trying to do something simple, but it won't let me.

    I have a bunch of cells with a simple math formula like
    =-(0.5*20)
    various values in each cell, multiplied by 20

    I simply want to change the multiplier globally from 20 to 25. But when I tell it to find *20 and replace it with *25, it replaces the entire cell contents with *25, rather than just replacing the *20 portion of the cell contents.

    Can anyone assist with this? Seems so simple, but Excel isn't letting me do it.

    • Hui... says:

      Search/Replace 20 or 20) with a cell Reference eg A1 or A1)
      Then put the value 25 in A1

      By using a * in the search it replaces all the text

  19. sadaqat says:

    how to find a specific cell's value in a column & replace replace it with another cell value i actually need a method to replace a data in ca column and replace with the value i have in a specific cell can i give a [ location ] of data to what i need to find and then give row or column range to where i need to find and the given value & then give a [ location ] of data to what i want to be replace with the find and replace by row & column range & than by specific criteria and than by specific location.
    please help.

  20. sadaqat says:

    how to find a specific cell’s value in a column & replace replace it with another cell's value.
    i actually need a method to find a specific cell's data in a column and replace it with the value i have in a specific cell.
    can i give a [ location ] of data to what i need to find and then give row or column range from where i need to find the given value & then give a [ location ] of data to what i want to be replace with.
    find and replace by row & column range & than by specific criteria and than by specific location.
    please help.

  21. sadaqat says:

    how to find a specific cell’s value in a column & replace it with another cell’s value.
    i actually need a method to find a specific cell’s data in a column and replace it with the value i have in a specific cell.
    can i give a [ location ] of data to what i need to find and then give row or column range from where i need to find the given value & then give a [ location ] of data to what i want to be replace with.
    "find and replace by row & column range & than by specific criteria and than by specific location."
    in more than 100 sheets in entire workbook
    please help.

  22. Juaninho says:

    This is a great tool, does anyone knows an easiest way??

    I'm working with a system that has over 59000 references... so every time the replace all is activated. I lose an entire day.

  23. sadaqat says:

    i actually needs to find cell number "D12" in column "D" and replace with Cell Number "B8" for example
    find what = Cell Number "D12" John McNamara
    find Where = in Column "D"
    Replace with = Cell Number "B8" Bieber D'Souza
    Replace Range = Column "D"
    In which Sheet = All Sheets in Work Book (more than 100 Sheets)
    Note: in every Sheet Cells Number "D12" & "B8" containing Different Employ Name but the find rang and replace rang are same in every sheet and find what cell number and replace with cell number are same also.
    please help!

  24. sara says:

    thank you. saved lot of time.

  25. Crystal says:

    Thank you from the bottom of my heart!

  26. Gerard says:

    Hi, I am trying to figure out how to use RE to find and replace several values in a column. Using find and replace does not work because of the values I am working with. I have a column with hundreds of rows that have a description of several operating systems and other info, which looks like this: Windows Server 2008 R2 Member Server Security Technical Implementation Guide; Windows 2008 Member Server Security Technical Implementation Guide; Solaris 10 10 SPARC SECURITY TECHNICAL IMPLEMENTATION GUIDE; and Windows Windows 2003 Member Server Security Technical Implementation Guide.

    I need to be able to find and replace (or basically curtail the descriptions) to be Windows 2008 R2; Windows 2008; Windows 2003; and Solaris 10. BUT when I run find and replace with just *2008*, it finds every instance, including the ones with R2 at the end. I need it to only change the ones with 2008 to Windows 2008 and the ones that have 2008 R2 to Windows 2008 R2. I know it is possible, but I have no clue on how to write a macro to do this.

    Thanks for your help,
    Gerard

  27. Paul says:

    Wickedly efficient workaround. Excel really is a powerhouse program, all you have to do is dig into it. Ctl ~ exposes the formulas, and Ctl H allows for the multi edit. Brilliant, Chandoo!

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