Dataset Expression Row Count

Ignition
1

I have a dataset and I would like to check to see if the dataset contains any rows in an expression binding. I know to access the dataset values, you use “Dataset_Expression [x,y]”. Is there a way to check how many rows are in the dataset, similar to data.getRowCount()?

2

You should be able to check the row count of a dataset in the expression language by simply using the len() function:

len({referenceToDataset})
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3

Note that this capability of the len() expression is new in 8.1.8, for any users still on an older version.

4

Do you mean somewhere it broke and was fixed for 8.1.8? Because this functionality goes way back.

5

I think he’s mixed up adding expanded support for arrays and collections. Looks like the len function has supported DataSets for a long time.

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6

How to get the length of a disticnt column values inside a dataset ?

7

All the columns will have the same length and this will be the length of the dataset.

Are you asking how to get the maximum string length in a particular dataset column? (If so then this should have been asked as a new thread as it is not related to this one.)

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8

Can I use python's len function to do the same thing within a script?

9

I'm not sure, I would probably just stick with the default dataset scripting functions in Ignition:

dataset.getRowCount()
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10

Not for any arbitrary dataset. PyDatasets, yes.

11

Slightly more efficient, and easier on the eyes:

dataset.rowCount
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