CODE EXAMPLE FOR PYTHON

python counter least common

from collections import Counter
data_list = [1,1,2,2,2,2,3,3,3,3,3,3,3,4,4,4,4,4,4,4]
least_common = Counter(data_list).most_common()[-1]
print(least_common)
# The number 1 appears 2 times
(1, 2)