2. First steps

Question 1

Function that gives the first element of a list.

Answer 1

> head [1,2,3,4]
1

Question 2

Function that removes the first element of a list.

Answer 2

> tail [1,2,3,4,5]
[2,3,4,5]

Question 3

Function that selects the nth element of a list.

Answer 3

> [1,2,3,4] !! 2
3

Question 4

Function that selects the first n elements of a list.

Answer 4

> take 3 [1,2,3,4,5]
[1,2,3]

Question 5

Function that removes the first n elements from a list.

Answer 5

> drop 3 [1,2,3,4,5]
[4,5]

Question 6

Function that gives the length of a list.

Answer 6

> length [1,2,3,4,5]
5

Question 7

Function that calculates the sum of a list.

Answer 7

> sum [1,2,3,4,5]
15

Question 8

Function that calculates the product of a list.

Answer 8

> product [1,2,3,4,5]
120

Question 9

Function that appends two lists

Answer 9

> [1,2,3] ++ [4,5]
[1,2,3,4,5]

Question 10

Function that reverses a list.

Answer 10

> reverse [1,2,3,4,5]
[5,4,3,2,1]

Question 11

How to put a function between it’s 2 arguments?

Answer 11

Use ` ` i.e. 6 div 3 = 2.

Question 12

How to specify variables after they’re used?

Answer 12

the where {} operator.
i.e. a = b + c where {b = 2, c = 3}

Question 13

How can we write comments?

Answer 13

– and {- -}

Question 14

Function to get last element of a list.

Answer 14

> last [1,2,3,4,5]
5

Question 15

Function to remove last element of a list.

Answer 15

> init [1,2,3,4,5]
[1,2,3,4]