Monadic function ∪/

Catenate reduction works on empty arrays, and gives an empty result with a prototype appropriate to the empty argument:

]display ,/⍬

┌─────┐ │ ┌⊖┐ │ │ │0│ │ │ └~┘ │ └∊────┘

]display ,/0⍴⊂⊂'' ''

┌─────────────────┐ │ ┌⊖────────────┐ │ │ │ ┌→────────┐ │ │ │ │ │ ┌⊖┐ ┌⊖┐ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ └─┘ └─┘ │ │ │ │ │ └∊────────┘ │ │ │ └∊────────────┘ │ └∊────────────────┘

Other enhancements

Version 15.0 introduced a family of system functions to handle native files, especially Unicode files, in a manner as easy as possible. However, creating and modifying files in the file system is inappropriate for a tutorial like this. You may instead find information about this in the release notes.