在 APL 中如何将字符串转换为一个单元格向量

Question

So, I have a function f that takes a string as input. I want to create a function g that maps f to a vector of strings. Ie

g 'Hello' 'world'

should yield

(f 'Hello')(f 'world')

Here's what I did:

g ← {f¨⍵}

And this works just fine for the example above. However, it doesn't work when the right argument is just one string, as it maps f to every character of that string. For example:

g 'Hello'

yields

(f 'H')(f 'e')(f 'l')(f 'l')(f 'o')

Of course, I wanted the output to be f 'Hello' .

I could write

g ← {f¨⊂⍵}

So that 'Hello' would be interpreted as

┌─────┐
│Hello│
└─────┘

But then 'Hello' 'world' will be interpreted as

┌─────────────┐
│┌─────┬─────┐│
││Hello│world││
│└─────┴─────┘│
└─────────────┘

And then it won't map correctly.

Is there a way to solve this succinctly?

Answer 1

You're looking for ⊆

      ⊆'hello'
┌─────┐
│hello│
└─────┘
      ⊆'hello' 'world'
┌─────┬─────┐
│hello│world│
└─────┴─────┘