爲什麼這不是打印出X，Y np陣列

Question

所以我有一個數據框activities_and_attractions與X，Y屬性數字。我想創建一個numpy的陣列

[X1，Y1]

[x2，y2]

[X3，Y3]

但事實證明，只打印最後一行

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

您需要在循環vstack輸出分配給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 

考慮使用numpy.append來執行此任務。以這種方式種植ndarrays效率不高。

出了什麼問題：

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