Formula Forensics No.004 – Fred’s Problem

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About 6 months ago, Fred asked a question on the Chandoo.org Forums: I need idea on a simpler formula

In column A I have the total sum product of C to AU
Line one has all the names.
A2 = (B2*C2)+(D2*E2)+(F2*G2)+(H2*I2)+(J2*K2)+(L2*M2)+…+(AT2*AU2)
A3 = (B3*C3)+(D3*E3)+(F3*G3)+…+(AT3*AU3)

Is there is simpler way by line to do this without clicking each cell on line 2?

I tried Sumproduct but I think I have received a wrong answer during testing.

 

Hui offered a Sumproduct Formula as a solution

=SUMPRODUCT((B2:AT2) * MOD(COLUMN(B2:AT2) -1, 2), (C2:AU2) * MOD(COLUMN(C2:AU2), 2))

and then followed up with a simpler Sumproduct Formula a day later

=SUMPRODUCT(B2:AT2 * C2:AU2 * (MOD(COLUMN(B2:AT2), 2) =0))

Let’s take a look at this second solution.

 

Setup the Problem

Copy the numbers 10,20 into alternate Cells A2:U2 or download the example file here: Example File (Excel 97-2010)

Copy this formula into B6: =SUMPRODUCT(B2:U2 * C2:V2 * (MOD(COLUMN(B2:U2), 2)=0))


Pull The Formula Apart

Lets take a look inside this formula and see how it works.

=SUMPRODUCT(B2:U2*C2:V2*(MOD(COLUMN(B2:U2),2)=0))

We can see that in the above formula the main function used in the formula is a Sumproduct Function.

=SUMPRODUCT(B2:U2*C2:V2*(MOD(COLUMN(B2:U2),2)=0))

Within the Sumproduct function there are 3 arrays, which are multiplied together

Array 1: B2:U2

Array 2: C2:V2

Array 3: (MOD(COLUMN(B2:U2),2)=0)

What’s in these arrays?

Array 1 is simply the range from B2:U2

Array 2 is simply the range from C2:V2, note that it is offset from the first array by 1 Column.

This is so that the first value of the Second Array matches the first value of the First Array. That is they are both in position 1 within there respective arrays.

Array 3 is where all the action is.

Enter  =(MOD(COLUMN(B2:U2),2)=0) into a cell and press F9

Excel returns: ={TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE}

Lets look at what is happening here

=(MOD(COLUMN(B2:U2),2)=0)

Mod returns the remainder of the first value Column(B2:U2) after dividing it by the second value 2.

Column(B2:U2) returns the Column Number for each cell in the Range B2:U2.

Because this part of the formula is in a Sumproduct formula it is evaluated as an Array Formula and hence it does this for each cell in the range B2:U2, thus returning an Array as the answer.

We can see that if we enter =MOD(COLUMN(B2:U2),2) into a cell and evaluate it with F9

={0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1}

However in this case we want to convert this from an array of Numbers to an array of True/False

A simple addition of an =0 does the trick

=(MOD(COLUMN(B2:U2),2)=0)

Now causes the formula to return: ={TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE}

So How does this go together with the other 2 arrays?

We now have 3 arrays:

Array 110,20,10,20,10,20,10,20,10,20,10,20,10,20,10,20,10,20,10

Array 220,10,20,10,20,10,20,10,20,10,20,10,20,10,20,10,20,10,20

Array 3: TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE

When Multiplying arrays, Excel multiplies the first value of each array and then the second value of each array, etc, effectively doing

={10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True, 20*10*False , 10*20*True}

You can see above that when the 3 arrays are multiplied it will only be the Odd entries in Arrays 1 & 2 which are evaluated by the Sumproduct, as all the even entries are multiplied by False which is equivalent to Zero

So the above evaluates to

={200,0, 200,0, 200,0, 200,0, 200,0, 200,0, 200,0, 200,0, 200,0, 200}

Sumproduct then takes over and adds the values together returning, 2000, the correct answer.

 

Problem Extension

After solving the problem, Fred decided to add a column between each entry in the data set.

The solution is posted in the forum and is also shown in the example file.

You can work through that formula at your leisure, except to say that it is similar to the solution above.

Alternate Solution

Luke correctly pointed out that the data was poorly arranged and the solution would be much simpler had the data been more logically arranged.

However as an Excel practioner we are often called to solve other peoples dirty work.

 

HINTS

You will notice that in the solution of this problem I have done a few small things that make solving the problem easier.

Use Smaller Subsets of the Data.

Instead of putting numbers from Columns B to AU as Fred has I have used a set from Column B to U.

This way I can see all the data on one Excel screen without scrolling as well as the formula links and extents when pressing F2 on the cell containing the formula.

Use Simple Numbers

Use numbers that you can manually check. In this example I can easily, manually, check that the answer should be 2000.

Evaluate

Where ever possible, enter sections of a formula in a cell and evaluate its output:

=(MOD(COLUMN(B2:U2),2)=0) and press F9

={TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE,TRUE,FALSE}

See how easily we can check that this section is returning the correct values.

 

OTHER POSTS IN THIS SERIES:

You can learn more how to pull Excel Formulas apart in the following posts:

http://chandoo.org/wp/category/formula-forensics/

The link above, will show you all the posts in this series

 

WHAT FORMULAS WOULD YOU LIKE EXAMINED?

If you have any formulas you would like explained please feel free to leave a post here or send me an email:

If the formula is already on Chandoo.org or Chandoo.org/Forums, simply send the link to the post and a Comment number if appropriate.

If sending emails please attach an Excel file with the formula and data

 

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33 Responses to “Show Months & Years in Charts without Cluttering”

  1. eladberko says:

    Very CooOOOoool 🙂

  2. JP says:

    Would it work if I merely change the display format for the dates, or do they actually need to be retyped in that format (Nov, Dec, etc)?

    ps- it's only about 34 donuts per month, or slightly more than 1 per day. Yum!

  3. Jon Peltier says:

    To make it work automatically when you create a chart, delete the labels above the Year and Month columns, but keep the label above the Y data (Donuts). The blank cells tell Excel that the first row and first two columns (indicated by the blanks) are special, so it uses the first row for series names an the first two columns for X axis labels.
     
    This is better than the other kind of donut chart, but you'll soon be carrying a big donut around your midsection.

  4. Erin Smith says:

    First off, thank you Chandoo for being respectful and taking out the "Jesus" comment. Not that I'd threaten to kill you, or start world-wide riots, or make you go into hiding if you didn't (as OTHERS would; wink, wink, nudge, nudge)... I just really appreciate your respectulness and consideration; so thank you. I was meaning to write you about it, but when I came to your site you'd already made the edit... so again, thank you!

    Secondly, I wanna say I think there's an easier way to do what you are demonstrating. I've got a pivot chart with months of data and all I had to do was right-click the x axis and then select "format axis", under "Axis Options" there's a check-box that says "Multi-level Category Labels". The chart I was able to do this on was a pivotchart however so maybe it wouldn't be that easy for a non-pivotchart.

    Anyway, love the site. Keep up the good work. Thanks also for being so open about your success, it's very encouraging and motivating.

    God (aka Jesus) Bless. 🙂

  5. Terry Dukes says:

    Hi Chandoo - great site! Another option to save space is to simply rotate the orientation of the text by 90 degrees, so the dates read vertical rather than horizontal. However, I like the elegance of your solution also.

  6. Kien Leong says:

    Hey Chandoo -- Great tip. Only yesterday I was working through some strange behaviour with formatting dates in PivotCharts. Seems the axes never want to cooperate. This is a neat and elegant solution I hadn't thought of using. May need to abandon pivotcharts to use formulas like that, but if we use dynamic named ranges, no big sacrifice.

    BTW, whatever did you do to get your site blocked in China? Never heard of regime change by a grass-root spreadsheet movement. Maybe your ISP is hosting some problem sites. Chandoo.org is certainly worth it for me to fire up the VPN, but I'm sure you would lose a lot of other visitors from the middle kingdom.

  7. Kapil says:

    Chandoo ... pls help.. the link is blocked over here... pls can you put the regular link... 🙂

  8. Chandoo says:

    @JP... Excel Axis formatting is linked to cell formatting by default. So you can just have the dates which are formatted to look like months (mmm).

    @Erin: It was not my intention to mock anyone's faith or religion. I just used the word as it is quite common. I decided to remove it as I got 2 emails from readers requesting for the same.

    Also, the pivot charts take pivot table groupings by default, so you need not do any of the above while making charts from pivot tables.

    @Kein: I am not sure why Chinese authorities decided to block my site. I wish they would actually look at the content instead of blocking sites based on simple text matching rules.

    @Kapil: The file is mirrored here: http://chandoo.org/img/d/date-axis-months-years-trick.xls

  9. Prateek says:

    Cool, really cool...

  10. SS says:

    Nice one Chandoo,

    Also would like to mention abt useful method while creating dynamic charts.

    In any chart where in the months keep on adding - instead of changing the range for the chart every time we add a month, we can actually format the months as dates (probably 1st of every month) still keep the format as "mmm" AND while selecting the data, we can select a huge rows (date column) once and for all, and the chart adjusts automatically with the data that we entered. So next month when I enter Dec's data, I need not change the source data of the chart, however it automatically adjusts.

    Hope I made sense.!

    Regards,
    SS

  11. Tom says:

    Thanks, Chandoo! This is a great tip - one that I will definitely put to use. I typically have an axis with mmm yy format, aligned vertically, but this will definitely look a bit cleaner (except in cases where the chart is too small for the axis labels to be displayed horizontally, even without the mmm yy on one line). Thanks again!

    Tom

  12. Josh says:

    Chandoo,
    Thank you for the posts you are very diligent not to mention very helpful. I would like to know how to get the separation lines on the axis? For example your candy sales chart has longer lines separating east and west how do you format that?

    Thanks for being very awesome!
    -Josh

  13. Alvaro says:

    Hi Chandoo, we can look the formulas because there is a message:"Unsupported features".
    Could you send a diferent Link ?
    Thanks.

  14. Matt says:

    @SS But what if you've got formulas in the data block (i.e where you would enter static data for the month of december)? My chart now shows #N/A #N/A in the axis with no data for all future dates.

    Chandoo, I've got a dynamic range set up showing #N/A errors for future dates. The MMM-DD date format format in row works fine, but when I use YYYY and MMM in two rows, the axis shows #N/A #N/A for all future dates with no data. How would you go about keeping those future months hidden?

  15. Jon Peltier says:

    Matt -

    In order for the axis to automatically extend to the dates within the range and ignore #N/A at the end, you need a date-scale axis, and for this you need to use one column with the complete date, not two columns with year and month.

    If you want to use two columns, you need to generate Names in the worksheet which define ranges only as long as the number of months. I have a review of dynamic chart approaches in http://peltiertech.com/WordPress/dynamic-chart-review/ and a whole category on my blog at http://peltiertech.com/WordPress/category/dynamic-charts/. Chandoo also has examples of his own on this site.

  16. Ethan says:

    How do you make a dynamic chart out of this?
    I can't get the axis labels range right.
    I tried something like this:
    =OFFSET(REPORT!$H$10:$I$10;0;0;COUNTA(REPORT!$H$10:$I$100);1)

    Any idea?

  17. Jon Peltier says:

    Ethan -
     
    Your offset formula defines a range 1 row in size, but the technique here requires 2 rows. Your definition should end with
     
    ;2)
     
    instead of
     
    ;1)

  18. Ethan says:

    Thanks Jon,
    Got it working now

  19. Neal says:

    Great! Now, is there any way to do this directly in Powerpoint? I don't like having linked excel files, so I create the graphs right inside Powerpoint, any way to do this there? I tried and was unsuccessful.

    Thanks.

  20. Joe says:

    Cool tip Chandoo......thanks

  21. [...] extract year and month from dates to avoid a mess in our stock chart. Chandoo has a great post: Show Months & Years in Charts without ClutteringIn cell B2:=YEAR(D2)In cell B3:=IF(YEAR(D3)=YEAR(D2), "", YEAR(D3))Cell C2:=IF(TEXT(D2, [...]

  22. Bilal says:

    Hi there,
    I have got a data ranging for 3 years. I want to show a chart which shows Jan of 2011, 2012 and 2013 together side by side; then Feb11, Feb12 and Feb13 side by side, then Mar11, Mar12 and Mar13, and so on until December.
    Please help. Thanks.

  23. Down With This Sort Of Thing says:

    Hi there

    Very good solution this. I have another question on it, though. How do you format the X-axis with monthly gaps (ie, with labels "Jan 2012", "Apr", "Jul", "Oct", "Jan 2013", "Mar", etc), when you're dealing with a data series with weekly or daily data points? The Axis Options dialogue box doesn't appear to offer "Date axis" as an option under the "Axis Type" section.

    I've managed to do it in one case with weekly data by setting the interval between tick marks at 13 -- the approximate number of weeks in a quarter -- to get 3-month intervals. But this wouldn't work if I wanted to show 1-month intervals, or had a more detailed daily data series to work with.

  24. Herro says:

    Any luck getting the dates to work on a scatter graph? I'm only getting numbers. Works fine on line graphs though.

  25. Apoorve says:

    How can we do the vice versa? i.e. on the x-axis showing year on the level 1, and months on level 2.
    I wanted to build these kind of axis labels for 5 years, with year on top and months at the bottom, but it should form in such a way that the seperating lines should seperate the entire data set only at December of each year, and no lines in between any month.

  26. Carlos says:

    Like!!
    Three times already today I have used this website and saved a ton of work time in researching excel tricks.

    Suggestion: Why not have a "like" or "this article was useful to me" button. That way you can see what is most useful by your users and maybe generate more content based on those "likes".

    Just saying. Thanks again and you're doing a great job!

  27. Haj says:

    Thanks for the tip. However, I couldn't download your file. The link is broken.

  28. JeteMc says:

    Thank You for taking the time to post this tip. I hope that you have a blessed day.

  29. Tom says:

    The link does not work properly and I'm not sure how to actually get the graph to display like this, its frustrating me a tonne. I cant work out what to google either to find an answer elsewhere! 🙁

  30. parag says:

    Is this possible with waterfall chart. Data hereunder -

    Years Abbrevation Amt

    2020 BEG 2,006
    REV 1,950
    EMP 1,058
    DM (3,244)
    OOE 1,078
    OPMT 182
    AB (638)
    END 2,392
    2021 REV 8,534
    EMP 67
    DM (2,142)
    OOE (3,120)
    OPMT 510
    AB 1,008
    END 7,249

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