028_列操作

import pandas as pd
import numpy as np

if __name__ == '__main__':
    page_1 = pd.read_excel("C:/Users/18124/Desktop/pandas/027_行操作/Students.xlsx", sheet_name="Page_001")
    page_2 = pd.read_excel("C:/Users/18124/Desktop/pandas/027_行操作/Students.xlsx", sheet_name="Page_002")
    # print(page_1.head())
    # print(page_2.head())

    # 数据复制 - 从左到右
    students = pd.concat([page_1, page_2], axis=1)  # axis=1 : 数据 - 从左到右
    print(students)

    # 数据复制 - 从上到下
    students = pd.concat([page_1, page_2]).reset_index(drop=True)   # 默认axis=0 : 数据 - 从上到下
    print(students)

    # 追加新列
    students["Age"] = 25    # 初始数据 - 25
    students["Age"] = np.arange(0, len(students))   # 初始数据 - 递增
    print(students)

    # 删除列
    students.drop(columns=["Age", "Score"], inplace=True)
    print(students)

    # 插入列
    students.insert(1, column="Foo", value=np.repeat("foo", len(students)))
    print(students)

    # 修改列名
    students.rename(columns={"Foo":"FOO", "Name":"NAME"}, inplace=True)
    print(students)

    # 去掉空值
    students["ID"] = students["ID"].astype(float)   # 类型转换
    for i in range(5, 14):
        students["ID"].at[i] = np.nan
    print(students)

    students.dropna(inplace=True)   # 删除空值 : 删除条件 - 每行任意一列有空值