pd.mode()为pandas中求众数的函数，同时题目说名结果格式，得用DateFrame格式，Series格式将会报错

type(Nowcider.Level.mode()),type(Nowcider.loc[:,['Level']].mode())

4种解法

1. df[[""]]
2. df.loc[:,[""]]
3. df.iloc[:,["n"]]
4. pd.DataFrame(Nowcoder.Level.mode())

import pandas as pd

Nowcoder = pd.read_csv("Nowcoder.csv", sep=",")

# 解法一
# print(Nowcoder[["Level"]].mode())

# 解法二
# print(Nowcoder.loc[:, ["Level"]].mode())

# 解法三
print(Nowcoder.iloc[:, [1]].mode())

# 解法四
print(pd.DataFrame(Nowcoder.Level.mode()))