1、np.arange生成序列:
使用格式为如np.arange[first:step:last)
a=np.arange(1,5,.5)
print(a)
一个例子,比较np.arange与range
a=np.arange(1,5,.5) #步长可以为小数 print(a) b=list(range(1,5,2)) #步长只能为整数 print(b)
结果:
E:\Python36\python.exe E:/Pycharm/test/test.py
[1. 1.5 2. 2.5 3. 3.5 4. 4.5]
[1, 3]
Process finished with exit code 0
2、np.zeros(N)
用来生成一些全为0的数字
3、np.linspace
numpy.linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None)
a=np.linspace(1, 10, 5) print(a)
[ 1. 3.25 5.5 7.75 10. ]
a=np.linspace(1, 10, 9,endpoint=False) print(a)[1. 2. 3. 4. 5. 6. 7. 8. 9.]
a=np.linspace(1, 10, 9,retstep=True) #retstep用来设置是否现实步长 print(a)(array([ 1. , 2.125, 3.25 , 4.375, 5.5 , 6.625, 7.75 , 8.875,
10. ]), 1.125)
4、np.random.normal()
mu, sigma = 0, .1
s = np.random.normal(loc=mu, scale=sigma, size=1000)
print(s)
结果
[ 1.34706614e-01 7.27098324e-03 5.03454840e-03 1.00849012e-01
-8.27379913e-03 1.16168511e-02 -7.91991555e-02 -6.88258372e-02
-2.36020778e-01 -1.54646594e-02 1.43802819e-01 1.06134402e-01
1.13429440e-01 -7.34686819e-02 -6.02254276e-02 -4.94231847e-02
1.52000387e-01 1.41815695e-01 -2.39745654e-02 2.25509004e-02 .........]
mu, sigma = 0, .1
s = np.random.normal(loc=mu, scale=sigma, size=(2,3))
print(s)
结果
[[ 0.20542985 0.01118872 0.02855233]
[ 0.13037334 -0.02400409 -0.19085698]]
5、np.sqrt
np.sqrt对矩阵中每个元素都开方