I recently had to perform some analysis on a set of insurance companies in certain geography. After searching the net I found such list of companies operating in that continent. But the problem is,
- These companies are listed multiple times, one time for each of their geographical area of operation.
- I cannot count each company only once since there is geography specific operational data in that list.
- But at the same time, information pertaining to organization like total sales, strategy etc. are common to all the subsidiaries / separate entities of a company.
- There are too many companies to do the manual grouping of companies
I think this type of problems are fairly common in business analytics. So here is a relatively simple solution for getting unique list of companies without losing any information or writing macros. See the example for yourself.
Lets take an example of employee data. You have fields like Person Name (sometimes unique), Previous employment, Previous workplace, Previous Salary. Now, if person Anand worked in more than one place earlier, there will be more than one rows with his name. But for details like DOB, SSN etc. there wont be multiple rows. So you need to know how many uniques rows are there in that huge list. Detailed Steps:
- Enter / copy the data
- Sort the list on person name
- In the column next to prev-company enter the following formula in E2
=IF(OR(LEFT(B2,SEARCH(" ",B2))=LEFT(B3,SEARCH(" ",B3)),LEFT(B2,SEARCH(" ",B2))=LEFT(B1,SEARCH(" ",B1))),LEFT(B2,SEARCH(" ",B2)),B2)
Copy – paste the formula in all the cells in the list for the column. You will see the followin result.
- Now create one more column next to Unique Name with heading Unique?. Paste the following formula in the F2. Apply the formula to all the cells in the list.
=IF(E2=E3,0,1)
Now, you would see the list like this.
- Now sellect the top row and apply “auto filters” [Data->Filter->Auto-Filter] And select 1 in the Unique? column. You will see all the unique names. You can copy paste this list in another sheet/work-book and work with it or assign corresponding codes to each of the unique items in this list.
To summerize:
1. Sort your list first.
2. Get the unique parts like first word / first number etc in another column. In my case I had to use first word.
3. Compare consecutive rows and mark the differences. Now you know how many unique items you have.
Comments / Any better ways of doing this are always welcome.
8 Responses to “Pivot Tables from large data-sets – 5 examples”
Do you have links to any sites that can provide free, large, test data sets. Both large in diversity and large in total number of rows.
Good question Ron. I suggest checking out kaggle.com, data.world or create your own with randbetween(). You can also get a complex business data-set from Microsoft Power BI website. It is contoso retail data.
Hi Chandoo,
I work with large data sets all the time (80-200MB files with 100Ks of rows and 20-40 columns) and I've taken a few steps to reduce the size (20-60MB) so they can better shared and work more quickly. These steps include: creating custom calculations in the pivot instead of having additional data columns, deleting the data tab and saving as an xlsb. I've even tried indexmatch instead of vlookup--although I'm not sure that saved much. Are there any other tricks to further reduce the file size? thanks, Steve
Hi Steve,
Good tips on how to reduce the file size and / or process time. Another thing I would definitely try is to use Data Model to load the data rather than keep it in the file. You would be,
1. connect to source data file thru Power Query
2. filter away any columns / rows that are not needed
3. load the data to model
4. make pivots from it
This would reduce the file size while providing all the answers you need.
Give it a try. See this video for some help - https://www.youtube.com/watch?v=5u7bpysO3FQ
Normally when Excel processes data it utilizes all four cores on a processor. Is it true that Excel reduces to only using two cores When calculating tables? Same issue if there were two cores present, it would reduce to one in a table?
I ask because, I have personally noticed when i use tables the data is much slower than if I would have filtered it. I like tables for obvious reasons when working with datasets. Is this true.
John:
I don't know if it is true that Excel Table processing only uses 2 threads/cores, but it is entirely possible. The program has to be enabled to handle multiple parallel threads. Excel Lists/Tables were added long ago, at a time when 2 processes was a reasonable upper limit. And, it could be that there simply is no way to program table processing to use more than 2 threads at a time...
When I've got a large data set, I will set my Excel priority to High thru Task Manager to allow it to use more available processing. Never use RealTime priority or you're completely locked up until Excel finishes.
That is a good tip Jen...