I would like to convert all the values in a col that are not float (str, nan, etc) to some garbage value like -99 (I replace this later in my code). For example

```
1.23

!DIV0

5.55

<0 

10.2

nan 

```

I'd like the output to be

```
1.23

-99

5.55

-99

10.2

-99

```

I tried using `df.col.apply(lambda x: x.replace ...`

but it is using the str function replace and not the pd function

I don't think I can use `applymap` because another col in my dataframe is strings and I need to keep it that way