为什么这不是打印出X，Y np阵列

Question

所以我有一个数据框activities_and_attractions与X，Y属性数字。我想创建一个numpy的阵列

[X1，Y1]

[x2，y2]

[X3，Y3]

但事实证明，只打印最后一行

data = np.array([activities_and_attractions.X[0], activities_and_attractions.Y[0]]) 

for i in range(len(activities_and_attractions.index)): 
    np.vstack((data, np.array([activities_and_attractions.X[i], activities_and_attractions.Y[i]]))) 

print(data) 

Answer 1

您需要在循环vstack输出分配给data：

for i in range(len(activities_and_attractions.index)): 
    data = np.vstack((data, np.array([activities_and_attractions.X[i], activities_and_attractions.Y[i]]))) # assign to data 

考虑使用numpy.append来执行此任务。以这种方式种植ndarrays效率不高。

出了什么问题：

data = np.array((activities_and_attractions.X, activities_and_attractions.Y))