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numpy???Python???????????

numpy?Python?????????????????????????????????????????????????TensorFlow?PyTorch?????numpy???????????????????????????

numpy??????

numpy?Python????????????????????????????????????????????numpy???????????????????????????numpy????????Python??????????????????????????

numpy?????

1.1 ????

?numpy?????????????????????????np.array()???

arr = np.array([1, 2, 3])

???????????????????

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

1.2 ?????????

????????????shape???????

print(arr.shape)  # ???(2, 3)

1.3 ????

numpy???????????????????????????

• ????????????

print(arr[1, 1])  # ???6

• ????5????

print(arr[arr > 5])  # ???[6, 7]

• ???????????

print(arr > 5)  # ???[[False, False, False],               #          [False, False, False],               #          [False, False, True]]

1.4 ??????

numpy?????????????copy()???????

arr = np.array([[1, 2, 3], [4, 5, 6]])arr_copy = arr.copy()arr_copy[0, 0] = 10print(arr_copy)

1.5 ????

?????????hstack()?vstack()?concatenate()?????

• ??????????

print(np.hstack((arr1, arr2)))  # ???[[1, 2, 3], [4, 5, 6]]

• ??????????

print(np.vstack((arr1, arr2)))  # ???[[1, 2, 3], [1, 2, 3]]

• ???????

print(np.concatenate((arr1, arr2), axis=1))  # ???[[1, 2, 3], [4, 5, 6]]print(np.concatenate((arr1, arr2), axis=0))  # ???[[1, 4], [2, 5], [3, 6]]

1.6 ????????

numpy ???????????????

• ?0?9????

print(np.arange(10))  # ???[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

• ?????

print(np.linspace(0, 20, 5))  # ???[0., 5., 10., 15., 20.]

• ?????

print(np.logspace(0, 20, 5))  # ???[1., 10., 100., 1000., 10000.]

• ?????

print(np.zeros((3, 4)))  # ???[[0., 0., 0.], [0., 0., 0.], [0., 0., 0.]]

• ?????

print(np.ones((3, 4)))  # ???[[1., 1., 1.], [1., 1., 1.], [1., 1., 1.]]

• ?????

print(np.eye(3))  # ???[[1., 0., 0.], [0., 1., 0.], [0., 0., 1.]]

• ?????

print(np.random.rand(4, 4))  # ????????4x4??

????

numpy ????????????????????????????????????????

???

print(arr1 + arr2)  # ????????????????print(arr1 / arr2)  # ????????????????print(arr1 ** 2)   # ??????????????

?????

?????????transpose()?T?????

print(arr.transpose())  # ???????????print(arr.T)  # ??????????

????

??????????????????????np.linalg.inv()?????????

print(np.linalg.inv(arr))  # ?????????

?????

numpy ????????????????????

???

print(np.random.rand(10))  # ???10?[0,1)?????print(np.random.randn(10))  # ???10??????????print(np.random.randint(1, 10, 5))  # ???5?????

?????????????????????????

????

• ?????????????????????????????
• ???????????????????
• ????????????????????????

????????????????numpy???????????????????????????????????numpy???????????

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