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numpy?Python?????????????????????????????????????????????????TensorFlow?PyTorch?????numpy???????????????????????????
numpy?Python????????????????????????????????????????????numpy???????????????????????????numpy????????Python??????????????????????????
?numpy?????????????????????????np.array()???
arr = np.array([1, 2, 3])
???????????????????
arr = np.array([[1, 2, 3], [4, 5, 6]])
????????????shape???????
print(arr.shape) # ???(2, 3)
numpy???????????????????????????
print(arr[1, 1]) # ???6
print(arr[arr > 5]) # ???[6, 7]
print(arr > 5) # ???[[False, False, False], # [False, False, False], # [False, False, True]]
numpy?????????????copy()???????
arr = np.array([[1, 2, 3], [4, 5, 6]])arr_copy = arr.copy()arr_copy[0, 0] = 10print(arr_copy)
?????????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]]
numpy ???????????????
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 ????????????????????????????????????????
| ??? | ?? |
|---|---|
| + | ?????????? |
| - | ?????????? |
| * | ?????????? |
| / | ?????????? |
| % | ????????????? |
| n | ???????n?? |
???
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 ????????????????????
| ???? | ?? | ???? |
|---|---|---|
rand(d0, d1, ..., dn) | ??[0,1)????????? | d0, d1, ..., dn??????? |
randn(d0, d1, ..., dn) | ??????????? | ?? |
randint(low, high, size) | ?????? | low?????high?????size????? |
random_sample([size]) | ??[0,1)????? | size??????? |
choice(a, size) | ???a????????? | a?1????size????? |
???
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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