See the example below to find the number that appears once in the list.
def singleTimeAppaer(list):
response = []
for i in list:
appearance = 0
for k in list:
if k == i:
appearance = appearance+1
if appearance > 1:
response.append(i)
set_dif = set(list).symmetric_difference(set(response))
return set_dif
if __name__ == '__main__':
lst = [1, 2, 3, 4, 111, 12, 33, 44, 55, 66,
77, 1, 12, 33, 44, 55, 66, 77, 2, 3, 4, 222]
print(f'Elements those appear only once in list {singleTimeAppaer(lst)}')
Output:
Elements those appear only once in list {111, 222}