datatable.Namespace.__getitem__()

datatable.Namespace.
self
[
item
]
source

Retrieve column(s) by their indices/names/types.

By “retrieve” we actually mean that an expression is created such that when that expression is used within the DT[i,j] call, it would locate and return the specified column(s).

Parameters

item
int | str | slice | None | type | stype | ltype

The column selector:

int

Retrieve the column at the specified index. For example, f[0] denotes the first column, whlie f[-1] is the last.

str

Retrieve a column by name.

slice

Retrieve a slice of columns from the namespace. Both integer and string slices are supported.

None

Retrieve no columns (an empty columnset).

type | stype | ltype

Retrieve columns matching the specified type.

return
FExpr

An expression that selects the specified column from a frame.

See also