python – Pandas读取sql整数变为浮点数

我遇到了一个问题,当我使用pandas读取Mysql表时,一些列(参见’to_nlc’)曾经是整数变成了一个浮点数(之后自动添加.0).

任何人都可以搞清楚吗？或者一些猜测？非常感谢！

解决方法

问题是您的数据包含NaN值,因此int会自动转换为float.

我想你可以查看NA type promotions：

When introducing NAs into an existing Series or DataFrame via reindex or some other means,boolean and integer types will be promoted to a different dtype in order to store the NAs. These are summarized by this table:

Typeclass   Promotion dtype for storing NAs
floating    no change
object      no change
integer     cast to float64
boolean     cast to object

While this may seem like a heavy trade-off,in practice I have found very few cases where this is an issue in practice. Some explanation for the motivation here in the next section.