Clojure, transform collection to map - clojure

Question

I was wondering what was the best way to iterate over many collection to create a map in clojure. Actually i have 3 collection:
("Aujourd'hui" "Demain" "25.11" "26.11" "27.11" "28.11" "29.11")
("2 °C" "2 °C" "1 °C" "0 °C" "-3 °C" "-4 °C" "0 °C")
("8 °C" "6 °C" "4 °C" "2 °C" "1 °C" "1 °C" "5 °C")
And i like to create a collection of maps looking like this:
{:date Aujourd'hui :temp-min 2°C :temp-max 8°C}{...}
And know it should not be so difficult but I can't figure out how to do that right.
Thanks for your help !

Answer 1

We can use map to construct a hash-map for each index of the collections. When provided with more than two arguments, map moves through all the collections in parallel.
user> (let [dates '("Aujourd'hui" "Demain" "25.11" "26.11" "27.11" "28.11" "29.11")
mins '("2 °C" "2 °C" "1 °C" "0 °C" "-3 °C" "-4 °C" "0 °C")
maxes '("8 °C" "6 °C" "4 °C" "2 °C" "1 °C" "1 °C" "5 °C")]
(pprint (map #(hash-map :date %1 :temp-min %2 :temp-max %3) dates mins maxes)))
({:date "Aujourd'hui", :temp-max "8 °C", :temp-min "2 °C"}
{:date "Demain", :temp-max "6 °C", :temp-min "2 °C"}
{:date "25.11", :temp-max "4 °C", :temp-min "1 °C"}
{:date "26.11", :temp-max "2 °C", :temp-min "0 °C"}
{:date "27.11", :temp-max "1 °C", :temp-min "-3 °C"}
{:date "28.11", :temp-max "1 °C", :temp-min "-4 °C"}
{:date "29.11", :temp-max "5 °C", :temp-min "0 °C"})

Answer 2

The following function constructs a table as a sequence of records from column heading titles and sequence of columns:
(defn build-table [titles columns]
(apply map (fn [& xs] (zipmap titles xs)) columns))
There should be as many :titles as there are columns.
For example,
(build-table [:date :temp-min :temp-max] data)
where
(def data ['("Aujourd'hui" "Demain" "25.11" "26.11" "27.11" "28.11" "29.11")
'("2 °C" "2 °C" "1 °C" "0 °C" "-3 °C" "-4 °C" "0 °C")
'("8 °C" "6 °C" "4 °C" "2 °C" "1 °C" "1 °C" "5 °C")])
... produces
({:temp-max "8 °C", :temp-min "2 °C", :date "Aujourd'hui"}
{:temp-max "6 °C", :temp-min "2 °C", :date "Demain"}
{:temp-max "4 °C", :temp-min "1 °C", :date "25.11"}
{:temp-max "2 °C", :temp-min "0 °C", :date "26.11"}
{:temp-max "1 °C", :temp-min "-3 °C", :date "27.11"}
{:temp-max "1 °C", :temp-min "-4 °C", :date "28.11"}
{:temp-max "5 °C", :temp-min "0 °C", :date "29.11"})
This leaves all the data elements as strings. Converting them to numbers, preferably with units attached, can be tackled independently. As they are written, such as 2°C are not valid Clojure.