pandas 级联 concat append
连接的一个有用的快捷方式是在Series和DataFrame实例的append方法。这些方法实际上早于concat()方法。 它们沿axis=0连接
#encoding:utf8 import pandas as pd one = pd.DataFrame({ 'Name': ['Alex', 'Amy', 'Allen', 'Alice', 'Ayoung'], 'subject_id':['sub1','sub2','sub4','sub6','sub5'], 'Marks_scored':[98,90,87,69,78]}, index=[1,2,3,4,5]) two = pd.DataFrame({ 'Name': ['Billy', 'Brian', 'Bran', 'Bryce', 'Betty'], 'subject_id':['sub2','sub4','sub3','sub6','sub5'], 'Marks_scored':[89,80,79,97,88]}, index=[1,2,3,4,5]) print("one:") print(one) print("two:") print(two) rs = pd.concat([one,two]) print("rs = pd.concat([one,two])") print(rs) print("rs = pd.concat([one,two],keys=['x','y'])") rs = pd.concat([one,two],keys=['x','y']) print(rs) print("结果的索引是重复的; 每个索引重复。如果想要生成的对象必须遵循自己的索引，请将ignore_index设置为True:") print("rs = pd.concat([one,two],keys=['x','y'],ignore_index=True)") rs = pd.concat([one,two],keys=['x','y'],ignore_index=True) print(rs) print("观察，索引完全改变，键也被覆盖。如果需要沿axis=1添加两个对象，则会添加新列:") rs = pd.concat([one,two],axis=1) print(rs) print("rs = one.append(two):") rs = one.append(two) print(rs) print("append()函数也可以带多个对象:") rs = one.append([two,one,two]) print(rs) D:\Download\python3\python3.exe D:/Download/pycharmworkspace/s.py one: Marks_scored Name subject_id 1 98 Alex sub1 2 90 Amy sub2 3 87 Allen sub4 4 69 Alice sub6 5 78 Ayoung sub5 two: Marks_scored Name subject_id 1 89 Billy sub2 2 80 Brian sub4 3 79 Bran sub3 4 97 Bryce sub6 5 88 Betty sub5 rs = pd.concat([one,two]) Marks_scored Name subject_id 1 98 Alex sub1 2 90 Amy sub2 3 87 Allen sub4 4 69 Alice sub6 5 78 Ayoung sub5 1 89 Billy sub2 2 80 Brian sub4 3 79 Bran sub3 4 97 Bryce sub6 5 88 Betty sub5 rs = pd.concat([one,two],keys=['x','y']) Marks_scored Name subject_id x 1 98 Alex sub1 2 90 Amy sub2 3 87 Allen sub4 4 69 Alice sub6 5 78 Ayoung sub5 y 1 89 Billy sub2 2 80 Brian sub4 3 79 Bran sub3 4 97 Bryce sub6 5 88 Betty sub5 结果的索引是重复的; 每个索引重复。如果想要生成的对象必须遵循自己的索引，请将ignore_index设置为True: rs = pd.concat([one,two],keys=['x','y'],ignore_index=True) Marks_scored Name subject_id 0 98 Alex sub1 1 90 Amy sub2 2 87 Allen sub4 3 69 Alice sub6 4 78 Ayoung sub5 5 89 Billy sub2 6 80 Brian sub4 7 79 Bran sub3 8 97 Bryce sub6 9 88 Betty sub5 观察，索引完全改变，键也被覆盖。如果需要沿axis=1添加两个对象，则会添加新列: Marks_scored Name subject_id Marks_scored Name subject_id 1 98 Alex sub1 89 Billy sub2 2 90 Amy sub2 80 Brian sub4 3 87 Allen sub4 79 Bran sub3 4 69 Alice sub6 97 Bryce sub6 5 78 Ayoung sub5 88 Betty sub5 rs = one.append(two): Marks_scored Name subject_id 1 98 Alex sub1 2 90 Amy sub2 3 87 Allen sub4 4 69 Alice sub6 5 78 Ayoung sub5 1 89 Billy sub2 2 80 Brian sub4 3 79 Bran sub3 4 97 Bryce sub6 5 88 Betty sub5 append()函数也可以带多个对象: Marks_scored Name subject_id 1 98 Alex sub1 2 90 Amy sub2 3 87 Allen sub4 4 69 Alice sub6 5 78 Ayoung sub5 1 89 Billy sub2 2 80 Brian sub4 3 79 Bran sub3 4 97 Bryce sub6 5 88 Betty sub5 1 98 Alex sub1 2 90 Amy sub2 3 87 Allen sub4 4 69 Alice sub6 5 78 Ayoung sub5 1 89 Billy sub2 2 80 Brian sub4 3 79 Bran sub3 4 97 Bryce sub6 5 88 Betty sub5 Process finished with exit code 0
