NumPy初步使用

import numpy as np

np.array([1,2,3,4])
np.array([[1,2,3,4],[5,6,7,8]])

np.array([1,2,3,4]).tolist()

arr = np.array([[1,2,3,4],[5,6,7,8]])

print(arr.ndim)

print(arr.shape)

print(arr.dtype)

np.array([1,2,3,4], dtype=np.int32)

np.arrat([1.2,1.3,1.4], dtype=np.float64)

np.zeros(8)

np.ones((2,3))

np.empty((3,4))

arr1 = np.arange(1,8,2)

# [1 3 5 7]

np.linspace(0, 80, 5)

# [0 20 40 60 80]

np.arange(0,12).reshape((3,4))

# [[ 0,  1,  2,  3],
#  [ 4,  5,  6,  7],
#  [ 8,  9, 10, 11]]

a = np.arange(12).shape(3,4)

a.flatten()

a = np.arange(12).reshape(3,4)

a.transpose()

# 等同于

a.T

a = np.arange(12).reshape(3,4)

b = np.arange(12).reshape(4,3)

a + 1

a + b 

a - 1

a - b

a * 2

a * b

a / 2

a / b

# 平方
arr ** 2

# 点乘
np.dot(a, b)
a.dot(b)


np.sin(a)

a = np.arange(12)

b = a

c = a.clone()