创建 array 有很多 形式
关键字
array：创建数组dtype：指定数据类型zeros：数据全为0ones：数据全为1arrange：按指定范围创建数据linspace：创建线段
与 List 区别之一 : 没有逗号分隔
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| a = np.array([2,23,4])
print(a)
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[ 2 23 4]
int64
指定数据
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| a = np.array([2,23,4], dtype=np.int)
print(a.dtype)
a = np.array([2,23,4],dtype=np.int32)
print(a.dtype)
a = np.array([2,23.1,4.0], dtype=np.float)
print(a)
print(a.dtype)
a = np.array([2,23,4],dtype=np.float32)
print(a.dtype)
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int64
int32
[ 2. 23.1 4. ]
float64
float32
创建特定数据
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| a = np.array(
[
[2,23,4],
[2,23,4]
]
)
print(a)
"""
[[ 2 23 4]
[ 2 32 4]]
"""
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全零数组
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a = np.zeros((3,4))
"""
array([[ 0., 0., 0., 0.],
[ 0., 0., 0., 0.],
[ 0., 0., 0., 0.]])
"""
print(a)
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全一数组
同时也能指定这些特定数据的 dtype:
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| a = np.ones((3,4),dtype = np.int)
"""
array([[1, 1, 1, 1],
[1, 1, 1, 1],
[1, 1, 1, 1]])
"""
print(a)
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全空数组
array([[ 9.88131292e-324, 1.13635099e-322, 1.97626258e-323],
[ 9.88131292e-324, 1.13635099e-322, 1.97626258e-323]])
连续数组arange
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| a = np.arange(10,20,2)
"""
array([10, 12, 14, 16, 18])
"""
print(a)
b = np.arange(12)
b
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[10 12 14 16 18]
array([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11])
改变数据的形状reshape
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| a = np.arange(12).reshape((3,4))
"""
array([[ 0, 1, 2, 3],
[ 4, 5, 6, 7],
[ 8, 9, 10, 11]])
"""
a
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线段型数据linspace
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| a = np.linspace(1,10,20)
"""
array([ 1. , 1.47368421, 1.94736842, 2.42105263,
2.89473684, 3.36842105, 3.84210526, 4.31578947,
4.78947368, 5.26315789, 5.73684211, 6.21052632,
6.68421053, 7.15789474, 7.63157895, 8.10526316,
8.57894737, 9.05263158, 9.52631579, 10. ])
"""
a
|
也能进行 reshape 工作:
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| a = np.linspace(1,10,20).reshape((5,4))
"""
array([[ 1. , 1.47368421, 1.94736842, 2.42105263],
[ 2.89473684, 3.36842105, 3.84210526, 4.31578947],
[ 4.78947368, 5.26315789, 5.73684211, 6.21052632],
[ 6.68421053, 7.15789474, 7.63157895, 8.10526316],
[ 8.57894737, 9.05263158, 9.52631579, 10. ]])
"""
|
Reference
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