I need to compare different dataframes, but they have some irrelevant columns for comparing. 

I'm using select to filter out some columns, which I don't need. `.select(col("b.start"), col("b.end")`

But imagine, this select is much bigger. I'm using it in many places. 

It's duplicating the code and on top of that it reduce readability. 

Can I store it to some variable so I can change this

```
val remaining = difference_df.except(source_df.select(col("b.start"), col("b.end")))

```

into something like this

```
val my_select = ... .select(col("b.start"), col("b.end"))
val remaining = difference_df.except(source1_df.select(my_select))

val remaining = difference_df.except(source2_df.select(my_select))

```