DS with VM>1 : how to handle empty values ?

[guiot...@gmail.com]

Hi,

I have a private tag of VR DS with a VM>1. The last value is actually empty. So the DS appears as such:
"1.0\0.0\0.0\0.0\0.0\1.0\0.0\0.0\0.0\0.0\1.0\0.0\0.0\0.0\0.0\1.0\"

it's not clear to me whether the last backslash is meant to represent a true empty last value, or if it's wrongly used as a padding character.

I've searched the standard and google, to try to find whether you can have an empty value in a DS, and how it should be encoded. I have not found information about that, so I assume by default that the value above is correct : you can indeed have empty values in a multiple-valued DS tag. I could have this for instance : "1.0\\\\0.0"

Why I'm asking is because one of our commercial apps is throwing an error while anonymizing the dataset. it's configured to keep the private tags intact, but bugs on this one.
Interestingly, when simply parsing the data, the app correctly reads this field as an array of number and a last empty element :
[1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, ]

but when it tries to rewrite it, it doesn't work because it's trying to cast a null value into a number, which throws the error.

So i'm trying to find the culprit : is the modality creating a malformed tag with a forbidden empty value in a multi-valued DS ?
or is the app not correctly handling an allowed empty value in a multi-valued DS tag ?

thanks
Thomas

[Hervé Guillemet]

This situation is uncommon and I'm not sure there exist any numeric multiple-valued standard data element that is allowed to contain empty values.
But technically, at the encoding level, it is your app that is buggy and that should be able to write the empty (null) value.

Hervé