.copy in python code example
Example 1: example of a deep copy in python
# deep copy example in python
import copy
old_list = [[1, 1, 1], [2, 2, 2], [3, 3, 3]]
new_list = copy.deepcopy(old_list)
old_list[1][0] = 'BB'
print("Old list:", old_list)
print("New list:", new_list)
# OUTPUT
Old list: [[1, 1, 1], ['BB', 2, 2], [3, 3, 3]]
New list: [[1, 1, 1], [2, 2, 2], [3, 3, 3]]
Example 2: python copy list
# Performance analysis by River on Stack Overflow
METHOD TIME TAKEN
b = [*a] 2.75180600000021
b = a * 1 3.50215399999990
b = a[:] 3.78278899999986 # Python2 winner
b = a.copy() 4.20556500000020
b = []; b.extend(a) 4.68069800000012
b = a[0:len(a)] 6.84498999999959
*b, = a 7.54031799999984
b = list(a) 7.75815899999997
b = [i for i in a] 18.4886440000000
b = copy.copy(a) 18.8254879999999 # With `import copy`
b = []
for item in a:
b.append(item) 35.4729199999997
# NOTE: Only for shallow copies, use copy.deepcopy for nested lists
Example 3: .copy python
new_list = list.copy()
# returns a new list without modifying the orginal list.
Example 4: python copy list
a=[1,2,3,4]
b=a[:]
''' now b has all elements of a'''