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1. Sum of List Elements2. Largest Element in List3. Smallest Element in List4. Count Occurrences in List5. Remove Duplicates from List6. Merge Two Lists7. Intersection of Lists8. Union of Lists9. Sort List10. Reverse List11. Check if List is Sorted12. Find Second Largest Element13. Find N Largest Elements14. Clone / Copy List15. Rotate List16. Remove Empty Lists17. Flatten Nested List18. Find Common Elements of Two Lists19. List Slicing Programs20. Replace List Elements21. Remove Element by Value22. Count Prime Numbers in List23. Pair Sum Problem24. Unique Elements from Both Lists25. List Difference

Clone / Copy List in Python

items[:] and list(items) copy the list, not the name. Change one, the other stays.

BeginnerList ProgramsExample 14 of 25
clone-copy-list.py
1# Program to clone a list
2

3items = input("Enter list elements separated by space: ").split()
4

5clone1 = items[:]
6clone2 = list(items)
7

8print("Original:", items)
9print("Clone1:", clone1)
10print("Clone2:", clone2)

Output

Enter list elements separated by space: a b c
Original: ['a', 'b', 'c']
Clone1: ['a', 'b', 'c']
Clone2: ['a', 'b', 'c']

What's going on

clone = items does not copy. Both names point at the same list. Mutate one, both change. That bug eats evenings.

items[:] and list(items) make a new list with the same elements. Nested lists are still shared (shallow copy). For this page the elements are strings, so you will not notice.

After this program

If the idea is still fuzzy, read Day 5: Lists and List Methods in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 25 list programs, or see every topic on Python exercises.

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