Checking for blank cells?

Hi, It's not possible to check NaN in that way. You need to do 

Your wave assignments are also written incorrectly. TopHist[TopWave] makes no sense because TopWave is a wave and not an integer (same applies to the RHS).

Rather than write this in a loop, you can also probably do this by conditional wave assignment.

Does that mean a blank cell is exactly referred to as the number 2? What happens when I want to conditionally check for the number 2?

Would it make more sense if I did TopHist[TopWave][p], I had the impression that it was wave[rows][columns] but because it's a 1D wave I shouldn't have columns.

When you say conditional wave assignment do you mean

 Sorry, I'm not familiar with what you mean by conditional wave assignment.

NaN is not a number. This means you can't test it using == or !=. By definition it doesn't equal or not equal anything. The way to test it is to test its number type.

As I understand it you want to put 1 in the index of the wave TopHist if your condition is met? You can do this with

As I said, you just need an integer in the square brackets.

A conditional wave assignment would be something like:

This doesn't need to be in a loop, because it assigns each row of TopHist for all values of p. Check out the help topic for an explanation of how this works.

I updated the code to what you suggested, but it didn't seem to work for the 0th index. (I attached the output waves)

What do I look up in displayhelptopic to learn more about conditional wave assignment? Does p go all the way to the Nth row? Does this not work if TopWave and BotWave have different numpnts? How do I control the boundaries? and why is this preferential to a loop?  When I say it in plain language: I want to go through TopWave and BotWave to check for NaN, from i=0 to i=N.  For me, it seems that the most straightforward method is a loop. 

Sorry for all the questions, this has been super helpful I really appreciate it!

The reason row 0 doesn't work is that you have the extra line TopHist[i] = 1. The variable i initialises at 0 so you are changing that row after doing the correct assignment. I've confused you a bit with suggesting two solutions.

Try this:

p.s. please don't edit your OP - my replies don't make sense if you change the code that I'm commenting on. These threads are useful for people reading in the future trying to figure out the same thing.