First Class functions
Idempot - given the same input you get the same output
Write an expression to add up the numbers from 1 to 10 and return the overall total.
Create an expression to do the same calculation, but without having to write all the numbers. Hint: consider the functions called range and reduce.
range function generates a sequence of numbers and when given arguments it does so from a specific range. The second number is exclusive, so for 1 to 10 the second argument should be 11.
(range 1 11)
Unfortunately we cant just add the result of a range, because it returns a lazy sequence So the following will cause an error
(+ (range 1 11))
Using a function called
reduce we can calculate a single total value from all the numbers in the collection.
The reduce function take 2 arguments, the first is the function to apply to a data structure, the second is the data structure.
(reduce + (range 1 11)) (reduce + (1 2 3 4 5 6 7 8 9 10))