high order functions

Question 1

what is a high order function

Answer 1

a function that takes a function as a parameter, returns a function or both

Question 2

what are benefits of high order functions

Answer 2

allows flexible and reusable functions
allows you to encode common programming patterns(encapsulation)
enables function composition

Question 3

function composition

Answer 3

combining functions for complex behaviours

Question 4

what are some examples of high order functions

Answer 4

map
filter
foldr
all
any
(.)
takeWhile
dropWhile

Question 5

map

Answer 5

applies a function to all values in a list

Question 6

filter

Answer 6

selects every element that satisfies the function

Question 7

all

Answer 7

returns all elements that satisfy the function

Question 8

any

Answer 8

returns the first element that satisfies the function

Question 9

(.)

Answer 9

returns the composition of two functions

Question 10

takeWhile

Answer 10

takes elements from the start of the list that satsify the function/ predicate
stops when it gets to the first that doesnt

Question 11

dropWhile

Answer 11

drops elements from the start of the list that satsify the function/ predicate
stops when it gets to the first that doesnt

Question 12

foldr

Answer 12

recursive pattern
f[] = v
f(x:xs) = x # f xs
#: function

Question 13

local bindings

Answer 13

variables or functions that are defined within a limited scope
usually inside a function

Question 14

what can we use to do local bindings

Answer 14

where
let in

Question 15

let in

Answer 15

let: defines the local bindings
in: the bindings are only available in this expression

Question 16

where

Answer 16

introduces local bindings available for the entire function body

Question 17

foldr

Answer 17

recursively applies the given function to the list from right to left

Question 18

foldl

Answer 18

recursively applies the given function to the list from left to right

Question 19

list comprehension

Answer 19

constructs new lists from old lists

Question 20

what does list comprehension look like in haskell

Answer 20

[x^2 | x <- [1..5]]

Question 21

which part is the generator in list comprehension and why

Answer 21

x <- [1..5]]
states how to generate values for x

Question 22

dependant generator

Answer 22

when later generators depends on the variables introduced in the earlier generators

Question 23

what is the role of guards in list comprehension

Answer 23

the condition that limits the values that the generator can use

Question 24

zip

Answer 24

maps two lists to a list of pairs of their corresponding elements