online find duplicates in list code example
Example: count the duplicates in a list in python
some_list=['a','b','c','b','d','m','n','n']
my_list=sorted(some_list)
duplicates=[]
for i in my_list:
if my_list.count(i)>1:
if i not in duplicates:
duplicates.append(i)
print(duplicates)