data input column name
#### Code Sample, a copy-pastable example if possible

```
a = df[(df.Gold>=1)&(df.Gold.1>=1)]
```
#### Problem description

when I input a data series, it automatically name the variable name to 'Gold' and 'Gold 1' because the input has two 'Gold' column.
which leads to an issue when I want to use indexing. The dot is recognized as "Invalid Syntax".
My solution is to rename the column but I wonder if I miss anything or actually we can automatically name them as 'Gold_1' instead of 'Gold.1' when this situation occur.


