numpy和pandas玩转数据

mport numpy as npa = np.array([[1,2,3],[2,3,4]])print(a.shape)print(a.ndim)print(a.size)print(np.sum(a))print(np.sum(a,axis=1))print(np.cumsum(a))print(np.transpose(a))a = np.zeros((3,4))print(a)b = np.arange(10,20,2)print(b)c = np.linspace(1,10,6).reshape((2,3))print(c)a = np.array([1,2])b = np.array([3,4])c = np.dot(a,b)print(c)print(a*b)print(np.vstack((a,b)))print(np.hstack((a,b)))

import pandas as pdimport numpy as nps = pd.Series([1,3,np.nan,4])print(s)dates = pd.date_range('20160101',periods=6)print(dates)df = pd.DataFrame(np.random.randn(6,4),index=dates,columns=['a','b','c','d'])print(df)print(df.loc['20160101'])df.iloc[2,2] = 989print(df)