Standard ML code Write a function firstN that takes a list and an int n and retu
ID: 3744542 • Letter: S
Question
Standard ML code
Write a function firstN that takes a list and an int n and returns the first n elements in the list. The type of firstN should be string 'a list -> int -> 'a list. If the input list is empty or if the length of the list is less than n, then the function should return the complete list. (You may assume that n is greater than 0.)
Examples:
> firstN ["a", "b", "c", "x", "y"] 3
["a", "b", "c"]
> firstN [1,2,3,4,5,6,7] 4
[1,2,3,4]
> firstN [1,2,3,4,5,6,7] 10
[1,2,3,4,5,6,7]
> firstN [[1,2,3],[4,5],[6],[],[7,8],[]] 4
[[1,2,3],[4,5],[6],[]]
> firstN [] 5 /*may give a warning*/ []
Explanation / Answer
def firstN(arr,val):
arr2=list() #creating new list to store output
if(len(arr)==0):
print('no elements in the list')
else:
for i in range(0,val): #coping the array elements to output list
arr2.append(arr[i])
print(arr2)
if __name__ == '__main__':
print('enter list')
arr = list(map(str, input().split())) #we are taking input from user input should be space separated
print('enter how much lenght you print')
var=int(input()) #this value should be in new line
firstN(arr,var) #passing to function
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