Clojure-地图功能

Question

As we know, (map f [abc]) is equivalent to [(fa) (fb) (fc)] .

My question is: The evaluation result of (map #(- (int %) (int \\0)) "1234") is (1 2 3 4) , why does it return the results of applying #(- (int %) (int \\0)) to every digits of "1234", rather than the string "1234" as a whole? How should I understand this code example?

Answer 1

map calls seq on all arguments after the first. seq turns a string into a sequence of characters.

Answer 2

Clojure can treat a string as a sequence - of characters. This is useful because you can:

• map things over the string
• partition the string
• get locations by index
• do everything else sequences do.

It's perhaps a bit annoying having to remember to put the resulting sequence back into a string by wrapping the sequence manipulating expression in a call to str .