datatable.stype.__call__()

datatable.stype.

__call__

(

col

)

source

Cast column col into the new stype.

An stype can be used as a function that converts columns into that specific stype. In the same way as you could write int(3.14) in Python to convert a float value into integer, you can likewise write dt.int32(f.A) to convert column A into stype int32.

Parameters

col

FExpr

A single- or multi- column expression. All columns will be converted into the desired stype.

return

FExpr

Expression that converts its inputs into the current stype.

Examples

from datatable import dt, f df = dt.Frame({'A': ['1', '1', '2', '1', '2'], 'B': [None, '2', '3', '4', '5'], 'C': [1, 2, 1, 1, 2]}) df

	A	B	C
	str32	str32	int32
0	1	NA	1
1	1	2	2
2	2	3	1
3	1	4	1
4	2	5	2

5 rows × 3 columns

Convert column A from string stype to integer stype:

df[:, dt.int32(f.A)]

	A
	int32
0	1
1	1
2	2
3	1
4	2

5 rows × 1 column

Convert multiple columns to different stypes:

df[:, [dt.int32(f.A), dt.str32(f.C)]]

	A	C
	int32	str32
0	1	1
1	1	2
2	2	1
3	1	1
4	2	2

5 rows × 2 columns

See Also

dt.as_type() – equivalent method of casting a column into

another stype.