import numpy as np

xm1 = np.array([[1,2,3], [3,4,5], [6,7,9]])
print(xm1)

xm2 = np.arange(1,10) #또는 xm = np.array(range(1,10))
print(xm2)
print(xm2.reshape(3,3))

xm3 = np.arange(1,10).reshape((3,3), order='F')
print('xm3:', xm3)

print(xm3.shape)
print('length: ', len(xm3))
print('size:', xm3.size)

######### indexing

print(xm3[1,2])
print(xm3[:, 0])   # 첫 번째 열
print(xm3[0:2, :]) # 첫 두 행
xm2[3] = 11
print(xm2)
xm3[0, 2] = 11
print(xm3)