How do I find the duplicates in a list and create another list with them?

Question

How can I find the duplicates in a Python list and create another list of the duplicates? The list only contains integers.

Answer 1

Without converting to list and probably the simplest way would be something like below. This may be useful during a interview when they ask not to use sets

a=[1,2,3,3,3]
dup=[]
for each in a:
  if each not in dup:
    dup.append(each)
print(dup)

======= else to get 2 separate lists of unique values and duplicate values

a=[1,2,3,3,3]
uniques=[]
dups=[]

for each in a:
  if each not in uniques:
    uniques.append(each)
  else:
    dups.append(each)
print("Unique values are below:")
print(uniques)
print("Duplicate values are below:")
print(dups)