While preparing a project plan, I had a strange problem. I wanted to highlight all the project tasks that fall with-in a certain date range. At the lowest level, the problem is like this:
There are 2 ranges of dates (a,b) and (x,y) and I want to know if they overlap (ie at least one date common between a,b and x,y)
The formula for testing such a thing seemed tricky at first. So I drew the conditions on paper to get clarity on what we should test. Evidently, there are 4 ways in dates (a,b) can overlap with dates (x,y) as shown below:
Now, we can test for the overlap condition using a formula like this:
If x is between a and b
or a is between x and y
then overlap
else do not overlap
As you know, there is no formula in excel like isbetween(). So we have to break it up to 2 conditions and an AND() Formula. Finally the formula becomes,
=if(or(and(x>=a,x<=b),and(a>=x,a<=y)),"Overlap","Do not overlap")
Now, it seemed like quite a big formula for testing if 2 ranges of dates overlap.
So, I continued my quest for even shorter formula.
After sometime, I realized that if we test for non-overlap instead of overlap, we can write a shorter formula.
Do not understand? Let me explain.
While there are 4 ways in which (a,b) can overlap with (x,y), there are only two ways in which (a,b) cannot overlap with (x,y). See this to understand:
Now, testing above conditions is very straight forward in excel.
the formula becomes, =if(or(y<a,b<x),"Do not overlap","Overlap")
The formula is much shorter and easy to maintain.
I was able to use it to test if a set of tasks in the project plan are running between given dates (for eg. next week). All is well in the end.
How do you test overlap conditions?
Do you ever have to test overlap conditions? What kind of formulas have you used? Please share your formula tips & tricks using comments.
6 Responses to “A quick personal update”
Thank you for the personal update. It was quite encouraging and a breath of fresh air in my Inbox. Take care and stay safe.
David
Doctors advise:
Virus obstructs lungs with thick mucus that solidifies.
Consume lot hot liquids like tea, soup, and sip of hot liquid every 20 min
Gargle w antiseptic of lemon, vinegar, & hot water daily
It attaches to hair/clothes detergent kills it, when come from st go straight shower
Hang dirty clothes in sunlight/cold overnight or wash immediately.
Wash metal surfaces as it can live on them 9 days
Do not touch hand rails
Do not smoke
Wash hands foaming 20 sec every 20 min
Eat fruit/veg and up zinc levels.
Animals do not spread it
Avoid common flu
Avoid eat/drink cold things
If feel sore throat do above immediate as virus is there 3-4 days before descends into lungs
Would love help with my database mgt in excel.
Thanks for being thoughtful of us.
BTW How do you track your expenses/income in excel? Can you share the worksheet please.
Stay safe you and your family, best wishes.
Thanks for the update and happy to know that you and family are doing good. A 21 day lockdown has now been announced in India (I live around Kolkata) so it's uncertain times ahead. I check up on your wonderful articles often and will do so even more regularly now. Stay safe and God bless.
Hi from Argentina, I follow you for a lot of years now. We here are in a quarantine for 2 or 3 weeks, because the pandemia.
Excel is also my passion and I came here looking for a Num2Words formula, but in spanish. If anyone have it, please let me know.
Best regards.
Pablo Molina
La Rioja - Argentina
I'm glad to have your personal update. I'm from India & following you for so many years. Cheers to have any further personal update.