YBS405. Assignment 2 Due Date: December 04, 2020 at 23:55
- Create a list of lists in which each element in a list appears with the number of repetitions. Example input: [1,2,3,1,2,1,4,5,3] Example output: [[1,3], [2,2], [3,2], [4,1], [5,1]]
Solution: myList = [1,2,3,1,2,1,4,5,3] output=[]
for i in set(myList): c = myList.count(i) output.append([i,c]) print(output) 2. Definition: The element of a list can be an empty list, a number, or a list. The following examples conform to the above definition: Exampled: [1,2,3,4] Example2: [] Example 3: [[1,2], 2, [3,4]] Example 4: [[[1], [2]], [1], [3,3,4], 5] Take a list that conforms to the definition above and produce a flat list. The outputs for the above examples are as follows: Output 1: [1,2,3,4] Output 2: [] Output 3: [1,2,2,3,4] Output 4: [1,2,1,3,3,4,5]
Solution:
def flatten_list(liste): if len(liste) == 0: return liste if isinstance(liste[0], list): return flatten_list(liste[0]) + flatten_list(liste[1:]) return liste[:1] + flatten_list(liste[1:])
exampleone = flatten_list([1,2,3,4]) exampletwo = flatten_list([]) examplethree = flatten_list([[1,2], 2, [3,4]]) examplefour = flatten_list([[[1], [2]], [1], [3,3,4], 5])
print(exampleone) print(exampletwo) print(examplethree) print(examplefour)
- Write a code that take the two sets and generate their intersectsions Example Input: s1 = {1,2,3}, s2 = {a, b, 1,2} intersection (s1, s2) -> {1,2}
Solution: s1 = {1,2,3} s2 = {"a", "b", 1,2} print(s1&s2) print(s1.intersection(s2))
- Write the function that keeps the permutations of the elements of a given list in the sub-lists. Example Input: [1,2,3] Example Output: [[1,2,3], [2,3,1], [3,1,2], [1,3,2], [2,1,3], [3,2,1] ]] Note: it does not have to come out in the same order as original list.
from itertools import permutations inputlist = [1,2,3] output = [] perm = permutations(inputlist) for i in list(perm): output.append(list(i)) print(output)
- Write the code that extracts all subsets of a given set into a list: Example Input: {1,2,3} Example Output: [{}, {1}, {2}, {3}, {1,2}, {1,3}, {2,3}, {1,2,3}]
Solution:
import itertools inputlist = {1,2,3} output = [] for L in range(0, len(inputlist)+1): for subset in itertools.combinations(list(inputlist), L): if subset is None: output.append({}) else: output.append(set(subset)) print(output)
- Write the code that removes repetitive elements in a list Example input: [1,2,3,1,2,1,3,4] Example output: [1,2,3,4] Solution: inputList = [1,2,3,1,2,1,3,4] output = sorted(set(inputList)) print(output)