How to concat a string to xsl:value-of select="…?

Answer 1

You can use the rather sensibly named xpath function called concat here

Of course, it doesn't have to be text here, it can be another xpath expression to select an element or attribute. And you can have any number of arguments in the concat expression.

Do note, you can make use of Attribute Value Templates (represented by the curly braces) here to simplify your expression