List Comprehension

Question 1

Describe the syntax of a list comprehension

Answer 1

List comprehension has three parts viz., Output function, binding and predicate. This is expressed as [ | , ]

Question 2

explain [x*2 | x = 12]

Answer 2

for each number x in the range 1..10, output x*2, if the output is greater than or equal to 12

Question 3

rule for multiple predicates in a comprehension

Answer 3

an element should satisfy all predicates to be included in the output list

Question 4

Give a meaningful name for this function

st = [ c | c ]]

Answer 4

removeNonUpperCaseLtrsFromGivenString

Question 5

Evaluate [ x*y | x 50]

Answer 5

[55,80,100,110]

Question 6

What will be length of the output list from this comprehension?
[ x*y | x <- [8,10,11]]

Answer 6

9

Question 7

Describe functionality of this comprehension

length’ xs = sum [1 | _ <- xs]

Answer 7

Replace every element in the given list with 1 and calculate sum of it. This produces length of a given list