python3 copy list code example

Example 1: copy a list python

new_list = old_list.copy()
# or
new_list = old_list[:]

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: python copy list

a=[1,2,3,4]
b=a[:] 
''' now b has all elements of  a'''