How to clone or copy a list?

Question

What are the options to clone or copy a list in Python?While using `new_list = my_list`, any modifications to `new_list` changes `my_list` everytime.Why is this?

Answer 1

The code that you've posted looks as if it should create a copy (new_list) of an original (old_list). What is happening under the covers is that a new reference has been created that points to the original list. To put it another way, new_list and old_list point to the same object in memory. In order to create a new list that is a separate and distinct object in memory from old_list, try

new_list = old_list.copy() # Python 3 copy() method

# or

new_list = old_list[:] # Python 2 (slice)