numpy和pandas玩轉數據

mport numpy as np
a = 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 pd
import numpy as np

s = 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] = 989
print(df)