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 “Make VBA String Comparisons Case In-sensitive [Quick Tip]”
Another way to test if Target.Value equal a string constant without regard to letter casing is to use the StrCmp function...
If StrComp("yes", Target.Value, vbTextCompare) = 0 Then
' Do something
End If
That's a cool way to compare. i just converted my values to strings and used the above code to compare. worked nicely
Thanks!
In case that option just needs to be used for a single comparison, you could use
If InStr(1, "yes", Target.Value, vbTextCompare) Then
'do something
End If
as well.
Nice tip, thanks! I never even thought to think there might be an easier way.
Regarding Chronology of VB in general, the Option Compare pragma appears at the very beginning of VB, way before classes and objects arrive (with VB6 - around 2000).
Today StrComp() and InStr() function offers a more local way to compare, fully object, thus more consistent with object programming (even if VB is still interpreted).
My only question here is : "what if you want to binary compare locally with re-entering functions or concurrency (with events) ?". This will lead to a real nightmare and probably a big nasty mess to debug.
By the way, congrats for you Millions/month visits 🙂
This is nice article.
I used these examples to help my understanding. Even Instr is similar to Find but it can be case sensitive and also case insensitive.
Hope the examples below help.
Public Sub CaseSensitive2()
If InStr(1, "Look in this string", "look", vbBinaryCompare) = 0 Then
MsgBox "woops, no match"
Else
MsgBox "at least one match"
End If
End Sub
Public Sub CaseSensitive()
If InStr("Look in this string", "look") = 0 Then
MsgBox "woops, no match"
Else
MsgBox "at least one match"
End If
End Sub
Public Sub NotCaseSensitive()
'doing alot of case insensitive searching and whatnot, you can put Option Compare Text
If InStr(1, "Look in this string", "look", vbTextCompare) = 0 Then
MsgBox "woops, no match"
Else
MsgBox "at least one match"
End If
End Sub