With Maps

Maps allow you to model data with its contextual meaning. The keys of a map can give the context and the values are the specific data.

Note Define a shopping list of items you want, including how many of each item you want to buy

  1. (def shopping-list
  2.   {"cat food"  10
  3.    "soya milk" 4
  4.    "bread"     1
  5.    "cheese"    2})

Note Define a starwars characters, eg. luke skywalker, jarjar binks. The starwars character should include a name and a skill (it doesnt matter what these are).

Use the ‘get’ function to return the value of a given key, eg. name. Use keyworks to return a given value if you used keywords for the map keys.

In this answer we have defined three different starwars characters, all using the same map keys.

  1. (def luke   {:name "Luke Skywarker" :skill "Targeting Swamp Rats"})
  2. (def darth  {:name "Darth Vader"    :skill "Crank phone calls"})
  3. (def jarjar {:name "JarJar Binks"   :skill "Upsetting a generation of fans"})

Lets see what the specific skill luke has

  1. (get luke :skill)

When you use a keyword, eg. :name, as the key in a map, then that keyword can be used as a function call on the map to return its associated value. Maps can also act as functions too.

  1. (:name luke)
  2. (luke :name)

There are also specific functions that work on maps that give all the keys of a map and all the values of that map

  1. (keys luke)
  2. (vals luke)