机器学习之python基础库numpy

“”"
@theme numpy
@time 2018/12/14
@author lz
@content no.unique去重
“”"
import numpy as np
arr1=np.array([“java”,“java”,“C语言”,“C++”,“C#”,“Pyhton”])
print("-"*10,“原始数据”,"-"*10)
for i in arr1:
print(i)
print(“good”)
arr2=np.unique(arr1)
print("-"*10,“去重的数据”,"-"*10)
for j in arr2:
print(j)
print(“hello”)
运行结果:

“”"
@theme numpy
@time 2018/12/14
@author lz
@content no.where
“”"
import numpy as np
arr1=np.array([7,2,9,5,4])
arr2=np.array([4,6,8,10,12])
condition=arr1>arr2
result1=[x if c else y for (x,y,c) in zip(arr1,arr2,condition)]
result2=np.where(condition,arr1,arr2)
print(“使用python语法”,result1,“类型”,type(result1))
print(“使用np.where的语法”,result2,“类型”,type(result2))
运行结果：

“”"
@theme numpy
@time 2018/12/14
@author lz
@content where函数
“”"
import numpy as np
arr1=np.random.randint(1,9,size=(3,3))
arr2=np.where([[False, False], [True, True]],
[[1, 2], [3, 4]],
[[9, 8], [7, 6]])
print(arr2)
运行结果