duplicated items in a list code example

Example 1: 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)

Example 2: how to find duplicate numbers in list in python

l=[1,2,3,4,5,2,3,4,7,9,5]
l1=[]
for i in l:
    if i not in l1:
        l1.append(i)
    else:
        print(i,end=' ')