pandas处理数据小技巧

import numpy as np
import pandas as pd

# 读取数据
df = pd.read_excel('E:/PythonData/data/pdata.xlsx')
print(df)

# 按照条件填充空值
values = {'English': 0, 'Math': 0, 'Language': 0}
df.fillna(value=values, inplace=True)
print(df)

# 使用apply函数更新数据
def average(*list):
    sum = 0
    if len(list)==0:
        return 0
    else:
        for i in list:
            sum = sum + i
        avg = sum / len(list)
        return avg

#--使用apply函数根据已有的列更新或者新增一列
df['Average'] = df.apply(lambda row:average(row['English'],row['Math'],row['Language']),axis=1)
df['Math']=df.apply(lambda row:average(row['English'],row['Math'],row['Language']),axis=1)
print(df)