how to make a double null?

[unknown00]

if you wire a constant 0 to it it sets the value as 0. i need it to be deleted, set to null. what do i wire to it?

[tst]

Numerics in LV do not have the concept of a null value. The closest is NaN which is an invalid value. You can get it simply by typing that into a numeric constant.

What is it exactly that you want to delete?

To learn more about LabVIEW, I suggest you try searching this site and google for LabVIEW tutorials. Here, here, here, here, here and here are a few you can start with and here are some tutorial videos. You can also contact your local NI office and join one of their courses.
In addition, I suggest you read the LabVIEW style guide and the LabVIEW user manual (Help>>Search the LabVIEW Bookshelf).

[altenbach]

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@unknown00 wrote:
if you wire a constant 0 to it it sets the value as 0. i need it to be deleted, set to null. what do i wire to it?

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What is "it"??? (binary string, formatted string, numeric, etc.)
How is "it" formatted?? (\-codes, hex display, hex format, ...)

[unknown00]

i tried using NaN but doesn't work. it just shows up as a string "NaN"

it refers to a double numeric indicator in an array. altenbach remember you kind of helped me out with this before, but instead in the past i needed to know how to set a string as null instead of a string as a blank value in an array? kinda the same thing but now instead of a string it's a double


//EDIT: i want to delete a numeric double value. 0 is still a value so it will still be analyzed i need it so it's "null" so it won't

Message Edited by unknown00 on 07-05-2007 02:48 PM

[mikeporter]

Right click on the element and under the Data Operations submenu select Delete Element.

Mike...

[TCPlomp]

The showing of NaN in the array means that the value is NaN ( a IEEE xxxx standard), what you most likely need is a 'delete from array' function.
Since NaN generates errors on a lot of functions.

Ton

[unknown00]

mike that is exactly what i need but is there a way to do that without having to manually follow those steps?

//EDIT: oops my bad. it's not an array it's a cluster

Message Edited by unknown00 on 07-05-2007 02:56 PM

[mikeporter]

Yes, there is also a delete element function under the array function menu.

Mike...

[unknown00]

again sorry it's not an array. here is a pic

[mikeporter]

For what it's worth, NaN does not generate errors in a lot of functions. Rather it propagates itself in very predictable and standardized ways. For example, any calculation where NaN is an operand will result in NaN - maybe inconvenient, but not an error. This is the way it is supposed to work. Likewise any comparison involving a NaN will evaluate to false - again, the way it is supposed to work.

Working with floating-point data requires care if you are to avoid getting into trouble. So if NaN causes an error in my code, that is my fault. I should have written it better.

Mike...