select

select(__data, *args, **kwargs)

Select columns of a table to keep or drop (and optionally rename).

Parameters

Name	Type	Description	Default
__data		The input table.	required
*args		An expression specifying columns to keep or drop.	()
**kwargs		Not implemented.	{}

Examples

>>> from siuba import _, select
>>> from siuba.data import cars

>>> small_cars = cars.head(1)
>>> small_cars
   cyl   mpg   hp
0    6  21.0  110

You can refer to columns by name or position.

>>> small_cars >> select(_.cyl, _[2])
   cyl   hp
0    6  110

Use a ~ sign to exclude a column.

>>> small_cars >> select(~_.cyl)
    mpg   hp
0  21.0  110

You can use any methods you’d find on the .columns.str accessor:

>>> small_cars.columns.str.contains("p")
array([False,  True,  True])

>>> small_cars >> select(_.contains("p"))
    mpg   hp
0  21.0  110

Use a slice to select a range of columns:

>>> small_cars >> select(_[0:2])
   cyl   mpg
0    6  21.0

Multiple expressions can be combined using _[a, b, c] syntax. This is useful for dropping a complex set of matches.

>>> small_cars >> select(~_[_.startswith("c"), -1])
    mpg
0  21.0