numpy有哪些常用函数,你能给我举点例子么
时间: 2024-05-05 19:21:11 浏览: 14
numpy是一个Python中常用的数学库,它提供了很多常用的函数,下面是一些常用函数的例子:
1. numpy.array:创建一个数组
```python
import numpy as np
a = np.array([1, 2, 3])
print(a)
# 输出: [1 2 3]
```
2. numpy.arange:创建一个一维数组,包含一个等差数列
```python
import numpy as np
a = np.arange(0, 10, 2)
print(a)
# 输出: [0 2 4 6 8]
```
3. numpy.linspace:创建一个一维数组,包含一个等间隔数列
```python
import numpy as np
a = np.linspace(0, 1, 5)
print(a)
# 输出: [0. 0.25 0.5 0.75 1. ]
```
4. numpy.random.rand:生成一个随机数组
```python
import numpy as np
a = np.random.rand(3, 3)
print(a)
# 输出:
# [[0.21582369 0.78743589 0.16844188]
# [0.17769027 0.41524925 0.80091012]
# [0.12160601 0.7926655 0.02280317]]
```
5. numpy.sum:计算数组的总和
```python
import numpy as np
a = np.array([[1, 2], [3, 4]])
sum_a = np.sum(a)
print(sum_a)
# 输出: 10
```
6. numpy.mean:计算数组的平均值
```python
import numpy as np
a = np.array([1, 2, 3, 4])
mean_a = np.mean(a)
print(mean_a)
# 输出: 2.5
```
7. numpy.std:计算数组的标准差
```python
import numpy as np
a = np.array([1, 2, 3, 4])
std_a = np.std(a)
print(std_a)
# 输出: 1.118033988749895
```
8. numpy.dot:计算两个数组的点积
```python
import numpy as np
a = np.array([1, 2])
b = np.array([3, 4])
dot_ab = np.dot(a, b)
print(dot_ab)
# 输出: 11
```
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