The number of individual elements of Python hit list

statistical methods

• Use Python dictionary statistics
• Use Python's collection packet statistics class at Counter
• Value_counts use of pandas in the Python package of statistical category

1, using the dictionary dict to complete statistics

import random
a = [ random.randrange(1,9) for x in range(10)]
data = {}
for key in a:
    data[key] = data.get(key, 0) + 1
print(data)

2, the use of collection bags Counter

from collections import Counter
import random
a = [ random.randrange(1,9) for x in range(10)]
result = Counter(a)
print(dict(result))

3, using the method in pandas packet value_counts

import pandas as pd
import random
a = [ random.randrange(1,9) for x in range(10)]
result = pd.value_counts(a)
print(result)

Note:利用pandas下的value_counts()，不仅可以统计list中各个元素出现的个数，还可对矩阵中的元素进行进行统计 .
For example:

import pandas as pd
a = pd.DataFrame([[1,2,3],
                  [3,1,3],
                  [1,2,1]])
result = a.apply(pd.value_counts)
print(result)