006_函数填充_计算列

import pandas as pd


def add_2(x):
    return x + 2

if __name__ == '__main__':
    books = pd.read_excel("C:/Users/123/Desktop/pandas/006_函数填充_计算列/Books.xlsx", index_col="ID")
    print(books.tail(5))

    # 整列操作
    books["Price"] = books["ListPrice"] * books["Discount"]

    # 循环单列 - 全部遍历
    for i in books.index:
        books["Price"].at[i] = books["ListPrice"].at[i] * books["Discount"].at[i]

    # 循环单列 - 全部遍历
    for i in books.index:
        books.at[i, "Price"] = books.at[i, "ListPrice"] * books.at[i, "Discount"]

    # 循环单列 - 特定区间
    for i in range(5, 15):
        books.at[i, "Price"] = books.at[i, "ListPrice"] * books.at[i, "Discount"] + 100

    # 整列操作 - 自加2元
    books["ListPrice"] = books["ListPrice"] + 2

    # 整列操作 - apply
    books["ListPrice"] = books["ListPrice"].apply(add_2)

    # 整列操作 - apply
    books["ListPrice"] = books["ListPrice"].apply(lambda x: x + 2)


    print(books)