local-assignment-with-let.md

Assignment: let

When you are creating functions, you may want to assign names to values in order to reuse those values or make your code more readable.

Inside of a function, however, you should not use def, like you would outside of a function. Instead, you should use a special form called let.

• Reference: Assignment let

(defn average [& values]
  (let [number-of-values (count values)
        sum-of-values    (apply + values)]
    (/ sum-of-values number-of-values)))

(average 1.0 1.0 2.0 3.0 5.0)

Note::Define a function to process an address book contact

Address book contacts are defined in a map The return value should be a string of name, address and email

Use a let expression to get each value from the contact hash-map Then join those values using clojure.string/join or str function

The call to the function would be (contact-details {:name "Sally" :address "Clojureville" :email "[email protected]"})

(defn contact-details [contact]
  "Replace me with your answer"
)
(contact-details {:name "Sally" :address "Clojureville" :email "[email protected]"})

Using clojure.string/join

(defn contact-details [contact]
  (let [name    (get contact-map :name)
        address (get contact-map :address)
        email   (get contact-map :email)]
    (clojure.string/join ", " name address email)))

(contact-details {:name "Sally" :address "Clojureville" :email "[email protected]"})

Using clojure.string/join

(defn contact-details [contact]
  (let [name    (get contact-map :name)
        address (get contact-map :address)
        email   (get contact-map :email)]
    (str name ", " address ", " email)))

(contact-details {:name "John" :address "Clojureville" :email "[email protected]"})