NaN values in array

[K.Waris]

Hello

I had a code done by my colleague who is not working with us anymore. In an array 8 columns and programmatically generated no. of rows all values initialize as NaN values. I have never come across NaN values before.

From research I gather it is not a number but it really isn't making much sense to me. Why the cells in array are written as NaN? What is the significance of NaN? Can I leave the cells empty and not showing NaN in it?

Kind Regards

Austin

[vt92]

A NaN result is generally caused by a divide by zero.

NaN is sometimes used to initialize data to "flag" the software that a value hasn't been updated or that an error has occurred.

[GerdW]

Hi Austin,

as long as it is an array of floating point numbers you cannot make empty "cells".

NaN is a standard floating point number, the same goes for +/-Inf. It's part of the standard!

---

Why the cells in array are written as NaN?

---

Either you initialize the array with NaNs or you compute the array content with NaN as result of that computation...

[Mads]

"Not a Number" in this context was probably used by your predecessor as the numeric equivalent of "empty" (we could call it "Not a known number").

NaN is typically used as a placeholder to indicate that no value is known for the given cell. Empty is not an option for numeric values, and using e.g.. 0 to indicate that the value has not been set might not be possible either because zero might just as well be a valid value for a filled cell.

[RavensFan]

NaN can have some useful purposes.  If you have a missing data point in the middle of a waveform graph, NaN means that datapoint doesn't get plotted.

[K.Waris · Accepted solution]

Ok. Yes I understand now the significance. So If I am creating an array in future and I want to set few rows to NaN values. How do I do it. Is there a Constant called NaN?

[GerdW]

Hi Austin,

for the constant you can use the standard numeric constant (set to any floating point format) and type "NaN" into it.

As NaN is a number you can type it into numeric inputs... (The same applies to +Inf and -Inf, they are standard numbers too!)

[Ben]

---

@GerdW wrote:

...

As NaN is a number :smileywink...

---

 Reading in expanded form "As Not a Number is a number" hurts a little every time I read it.

Ben

[JCC_(SK)]

Hi Austin

Your initialized array is filled up by value used for initialization by Initialization Array function.

See attached picture:

[johnsold]

No NaN constant currently is on the palettes.  It has been discussed in the Idea exchange.  If you like the idea, go to the idea exchange and give it a kudo.. Ideas with more kudos have a better chance of being incorporated into a future verson of LV.

Just drop a numeric constant on the block diagram and type "NaN" - actually it does not care about case so "nan" works also.

Lynn