turicreate.SFrame.apply

SFrame.apply(fn, dtype=None)

Transform each row to an SArray according to a specified function. Returns a new SArray of dtype where each element in this SArray is transformed by fn(x) where x is a single row in the sframe represented as a dictionary. The fn should return exactly one value which can be cast into type dtype. If dtype is not specified, the first 100 rows of the SFrame are used to make a guess of the target data type.

Parameters:

fn : function

The function to transform each row of the SFrame. The return type should be convertible to dtype if dtype is not None. This can also be a toolkit extension function which is compiled as a native shared library using SDK.

dtype : dtype, optional

The dtype of the new SArray. If None, the first 100 elements of the array are used to guess the target data type.

Returns:

out : SArray

The SArray transformed by fn. Each element of the SArray is of type dtype

Examples

Concatenate strings from several columns:

>>> sf = turicreate.SFrame({'user_id': [1, 2, 3], 'movie_id': [3, 3, 6],
                          'rating': [4, 5, 1]})
>>> sf.apply(lambda x: str(x['user_id']) + str(x['movie_id']) + str(x['rating']))
dtype: str
Rows: 3
['134', '235', '361']