您的解决方案并没有将它强制为整数;它在 row_id [0] 中创建一个元素数组（ Row 一。所以你最初可以只做 a_row [0] [0] 。

Your solution isn't forcing it into an integer; it is creating an array of the elements (the Rows) in row_id[0], and then extracting the first one. So you could have just done a_row[0][0] initially.