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:
[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.
12 Responses to “Analyzing Search Keywords using Excel : Array Formulas in Real Life”
Very interesting Chandoo, as always. Personally I find endless uses for formulae such as {=sum(if(B$2:B$5=$A2,$C$2$C$5))}, just the flexibility in absolute and relative relative referencing and multiple conditions gives it the edge over dsum and others methods.
I've added to my blog a piece on SQL in VBA that I think might be of interest to you http://aviatormonkey.wordpress.com/2009/02/10/lesson-one-sql-in-vba/ . It's a bit techie, but I think you might like it.
Keep up the good work, aviatormonkey
Hi Chandoo,
You might find this coded solution I posted on a forum interesting.
http://www.excelforum.com/excel-programming/680810-create-tag-cloud-in-vba-possible.html
[...] under certain circumstances. One of the tips involved arranging search keywords in excel using Array Forumlas. Basically, if you need to know how frequent a word or group of keywords appear, you can use this [...]
@Aviatormonkey: Thanks for sharing the url. I found it a bit technical.. but very interesting.
@Andy: Looks like Jarad, the person who emailed me this problem has posted the same in excelforum too. Very good solution btw...
Realy great article
"You can take this basic model and extend it to include parameters like number of searches each key phrase has, how long the users stay on the site etc. to enhance the way tag cloud is generated and colored."
How would you go about doing this? I think it would need some VB
Hi,
I found the usage very interesting, but is giving me hard time because the LENs formula that use ranges are not considering the full range, in other words, the LEN formula is only bringing results from the respective "line" cell.
Using the example, when I place the formula to calculate the frequency for "windows" brings me only 1 result, not 11 as displayed in the example. It seems that the LEN formula using ranges is considering the respective line within the range, not the full range.
Any hint?
@Thiago
You have to enter the formula as an Array Formula
Enter the Formula and press Ctrl+Shift+Enter
Not just Enter
Thank you, Hui! I couldn't work out how this didn't work
is there a limit to the number of lines it can analyse.
Ie i am trying to get this to work on a list of sentances 1500 long.
@Gary
In Excel 2010/2013 Excel is only limited by available memory,
So just give it a go
As always try on a copy of the file first if you have any doubts
Apologies if I am missing something, but coudn't getting frequency be easier with Countif formula. Something like this - COUNTIF(Range with text,"*"&_cell with keyword_&"*")
Apologies if I missed, but what is the Array Formula to:
1. Analyze a list of URL's or a list of word phrases to understand frequency;
2. List in a nearby column from most used words to least used words;
3. Next to the list of words the count of occurrences.