datatable.stype.__call__()¶
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 |
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 |
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 |
See Also¶
dt.as_type()
– equivalent method of casting a column intoanother stype.
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(CC BY 4.0) ,
and code samples are licensed under the MIT License.