I try to change a $DisplayExpression for the title of my notes.

As key attribute I have

Firstattribute  Cat
Secondattribute Dog

I want the result to be Cat: Dog

However, when I in the title pane of the text writes $Firstattribute+": "+$Secondattribute the result is

Cat;:;Dog

?

I have copy-pasted the information Cat and Dog from another system, and I suspect that doing this introduced some unwanted 'dirt'.

Do some of you have any suggestions about how to get rid of that?

BW

Marianne

Edited:

You're right! The eval() worked fine.

I found that using other than pre-defined attributes doesn't cause the same problem....

BW
Marianne

The underlying issue is the Data type of the attribute. The problem you originally described should only occur with List or Set types.

If you want to know the data type of an attribute, you can look at it in the Inspector. For system (built-in) attributes, you may find this list a quicker way to look things up.

When I spoke generically of a 'list' I was referring to all attribute that supports multiple values. Two of the attribute Data type in Tinderbox support multiple values: List or Set types. I commend following those links and reading the articles and exploring out from there in aTbRef. The main difference between Lists and Sets is sets do not support duplicate values.  If the 2 value of a List or Set were "Cat;Dog" (semi-colon is the value delimiter) then adding the value "Cat" would result in a List value of "Cat;Dog;Cat" but a Set would have the result "Cat;Dog" as the duplicate is ignored.

$Authors needs to be multi-value as a reference (book, paper, etc.) often has—outside fiction—more than one author. More specifically it is a Set-type attribute as duplicates in the attributes stored value(s) would be inappropriate.

So I don't see a mistake her.  If you look up what Set and List type do you'll see they are appropriate and that Set is a correct data type with $Authors.

The real issue here is that a single item list is still, under the hood, see a list consisting of one item. When using list attributes (i.e. List or Set data types) in action code you need to be aware that a reference to the attribute, e.g.$Authors, reference all values and you may need to use .format() to turn the value(s) into a string