learningcoder的专栏

# -*- coding:utf-8 -*-import pandas as pd# 一行转多行df = pd.DataFrame( {'Code': ['1111', '2222'], 'Color': ['a, b, c,d', 'blue, pink, yellow'], 'Size': ['1, 2, 3', '7, 6, 10']})id_df ...

df1df2join是按照行索引来关联操作,列名不能相同df1.join(df2) #返回df1的行数，df1和df2的所有列名 值没有的话用NaNmerge是按照列索引来关联操作，和关系型数据库很相近1. df1.merge(df2,on=0) #等价于df1.0=df2.0 0 1_x 2 3 4 1_y0 18 15 19...

# -*- coding:utf-8 -*-import pandas as pdimport numpy as np# DataFrame初始化 numpy.ndarraydf = pd.DataFrame(np.arange(12).reshape(3, 4), columns=["col" + str(i) for i in range(4)], index=list("ABC"...

# -*- coding:utf-8 -*-import pandas as pdimport string'''Series 对象是由两个数组组成，一个是索引(Index) 一个是值(values) 构造成键值对'''# Series数据初始化 列表s1 = pd.Series([1, 2, 3], index=["a", "b", "c"])print(type(s1))...

# -*- coding:utf-8 -*-import numpy as npt1 = np.arange(6).reshape(2, 3)t2 = np.arange(10, 16).reshape(2, 3)# 竖直拼接,vertically 相当于union all# print(np.vstack((t1, t2)))# 水平拼接 horizontally# print...

# -*- coding:utf-8 -*-import numpy as np# 和数字计算，广播计算(加，减，乘，除)t1 = np.arange(5)print(t1) # [0 1 2 3 4 ]print(t1 + 1) # [ 1 2 3 4 5]# print(t1 / 0) # [nan inf inf inf inf] nan=not a num...