How many ‘Friday the 13th’s are in this year? [Formula fun + challenge]

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Today is Friday the 13th. If you are a raging friggatriskaidekaphobiac, I suggest you to stop reading this post. For the rest of you, I have something fun.

Given a year in cell C3, let’s find out all the months with Friday the 13th. Something like this:

friday-13th-in-an-year

[Related: Finding next Friday the 13th using formulas]

Finding all Friday the 13ths in a year

Here is a formula to find the first Friday the 13th in a year.

{=IFERROR(SMALL(IF(WEEKDAY(DATE($C$3,ROW($A$1:$A$12),13))=6,ROW($A$1:$A$12)),1),””)}

Let’s understand how it works, going from inside out:

DATE($C$3,ROW($A$1:$A$12),13) portion: This generates an array of 12 dates, one for each 13th of the month in the year C3.

WEEKDAY(DATE(…))=6 portion: This checks how many of those dates are Fridays. Returns an array of TRUE / FALSE values.

IF(WEEKDAY(DATE(…))=6,ROW($A$1:$A$12)) portion: This returns an array of month numbers where we have Friday the 13th and FALSE values.

SMALL(IF(…),1) portion: This will give us the first month (ie 1st smallest value) with Friday the 13th in the year C3.

IFERROR() to suppress any errors.

To show all the Friday the 13ths in a year, simply replace 1 with an array of numbers (up to 3 should do).

Download Friday the 13th finder workbook

Click here to download Friday the 13th finder workbook. Enter a year in cell C3 and see all the months with Friday the 13th instantly.

A challenge for you…

If you are still reading, I have a challenge for you. Can you write a formula to find the next year with three Friday the 13ths? Assume the year is in C3. Post your formulas / VBA in the comment section.

hint: in the downloadable workbook, you can find an answer for this.

So that’s all for now. Enjoy your Friday the 13th.

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10 Responses to “Multiple Find Replace with Power Query List.Accumulate()”

  1. Ola says:

    Note: The text-formula above miss a -1. The video is correct.

  2. Ola says:

    😀 sorry, I made the exact same mistake as you did - initially - in the video. {0..3} is one thing, and Table.RowCount(replacements) -->3 items ={0,1,2} is another thing.

  3. yassine says:

    1st question : you've created a new column to put the replacements in. how ca we replace in the original column without creating a new one ?

    2nd question : how can we replace the value in the entire cell and not only the text (Using ReplaceValue instead of text.Replace) ?

    Thanks you in advance

  4. Noah says:

    Thank you for this! I was just doing an assignment where I was having to replace words with other words in my Excel sheet. We are starting with the basics in my class, so I know I don't have a huge list that I would need to find and replace, but this is something that could be useful down the road for me!

  5. Nick Ryder says:

    Hi

    This is nearly perfect for my needs thank you, however I would like just the "replace" to be the result if possible please, I have tried in vain adjusting the formula without success.

    Thank you in advance

  6. Huisie says:

    Thank you! Awesome tip, and very flexible, too.

    My find/replace values were in non-adjacent columns of a table containing a bunch of other data. Worked prefectly and I am now a tiny bit less clueless.

  7. Renata says:

    Hi!!!

    I have the same question that Yassine did.

    I need to replace the values in the same column. I don't want to create a new column e then have to remove the old column.
    How could I could that?

  8. That's a real fun article. It inspired me to delve deeper into the topic of List.Accumulate. I can see how the function works, but it takes an additional step to imagine how one can use it for more complex applications.

    Your example also made it into my article, together with some other use-cases. Would be great to get your opinion on which other areas you would include in the article.

    Let me drop the link to the page so others can too find it for further reading: https://gorilla.bi/power-query/list-accumulate/

  9. Muhannad says:

    Expression.Error: The name 'replacements' wasn't recognized. Make sure it's spelled correctly.

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