Suppose i want to change a number in a loop to a keyword in order to check an entry in a dict/map:
(def myarray {:p1 "test"})
#'user/myarray
user> (get myarray
(keyword ":p1")
)
nil
user> (get myarray
(symbol ":p1")
)
nil
user>
I am just getting nil returned. What do i miss here?
: is the indicator of keyword according to the Clojure guide, and the keyword function adds : automatically according to the Clojure Docs. So the correct code must be (keyword "p1") instead of (keyword ":p1").
Here is an outline of how you can do it:
(ns tst.demo.core
(:use demo.core tupelo.core tupelo.test))
(dotest
(let [m1 {:p1 "a"
:p2 "b"}
k1 (keyword (str "p" 1))
k2 (keyword (str "p" 2))
v1 (k1 m1)
v2 (k2 m1)]
(is= [k1 k2] [:p1 :p2])
(is= [v1 v2] ["a" "b"])))
Note though, an integer is a perfectly valid map key:
(dotest
(let [m1 {1 "a"
2 "b"}
k1 1
k2 2
v1 (get m1 k1) ; this doesn't work: (k1 m1 )
v2 (get m1 k2)]
(is= [k1 k2] [1 2])
(is= [v1 v2] ["a" "b"])))
You just have to use the get function (with the map as 1st arg!).
The above code is based on this template project.
(get {1 "test"} 1)