Finding first non-empty metadata tag

[monochrome]

Is there a variable expression that will iterate over a set of metadata tags and take the value of the first tag that is not empty?

For example, if I have some photos with CreateDate, some with DateTimeOriginal, some with DateTimeDigitized and some with all three, is there a variable expression that will give me CreateDate if it exists, if not, DateTimeOriginal, and if not that, DateTimeDigitized, and finally, nothing; but not all three?

[Mario]

Did you try to use the hasvalue function? You can chain them, making default the next variable to test for a value.

[monochrome]

Thanks! Didn't know they could be chained. The hasvalue function didn't make much sense to chain, but the "default" function did!

[Mario]

I think there might even be an example in the help.