# Copyright (C) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See LICENSE in project root for information.
import sys
if sys.version >= '3':
basestring = str
from pyspark.ml.param.shared import *
from pyspark import keyword_only
from pyspark.ml.util import JavaMLReadable, JavaMLWritable
from pyspark.ml.wrapper import JavaTransformer, JavaEstimator, JavaModel
from pyspark.ml.common import inherit_doc
from mmlspark.Utils import *
[docs]@inherit_doc
class SelectColumns(ComplexParamsMixin, JavaMLReadable, JavaMLWritable, JavaTransformer):
"""
``SelectColumns`` takes a list of column names and returns a DataFrame
consisting of only those columns. Any columns in the DataFrame that are
not in the selection list are dropped.
:Example:
>>> import pandas as pd
>>> from mmlspark import SelectColumns
>>> from pyspark.sql import SQLContext
>>> spark = pyspark.sql.SparkSession.builder.appName("Test SelectCol").getOrCreate()
>>> tmp1 = {"col1": [1, 2, 3, 4, 5],
... "col2": [6, 7, 8, 9, 10],
... "col2": [5, 4, 3, 2, 1] }
>>> pddf = pd.DataFrame(tmp1)
>>> pddf.columns
['col1', 'col2', 'col3']
>>> data2 = SelectColumns(cols = ["col1", "col2"]).transform(data)
>>> data2.columns
['col1', 'col2']
Args:
cols (list): Comma separated list of selected column names
"""
@keyword_only
def __init__(self, cols=None):
super(SelectColumns, self).__init__()
self._java_obj = self._new_java_obj("com.microsoft.ml.spark.SelectColumns")
self.cols = Param(self, "cols", "cols: Comma separated list of selected column names")
if hasattr(self, "_input_kwargs"):
kwargs = self._input_kwargs
else:
kwargs = self.__init__._input_kwargs
self.setParams(**kwargs)
[docs] @keyword_only
def setParams(self, cols=None):
"""
Set the (keyword only) parameters
Args:
cols (list): Comma separated list of selected column names
"""
if hasattr(self, "_input_kwargs"):
kwargs = self._input_kwargs
else:
kwargs = self.__init__._input_kwargs
return self._set(**kwargs)
[docs] def setCols(self, value):
"""
Args:
cols (list): Comma separated list of selected column names
"""
self._set(cols=value)
return self
[docs] def getCols(self):
"""
Returns:
list: Comma separated list of selected column names
"""
return self.getOrDefault(self.cols)
[docs] @classmethod
def read(cls):
""" Returns an MLReader instance for this class. """
return JavaMMLReader(cls)
[docs] @staticmethod
def getJavaPackage():
""" Returns package name String. """
return "com.microsoft.ml.spark.SelectColumns"
@staticmethod
def _from_java(java_stage):
module_name=SelectColumns.__module__
module_name=module_name.rsplit(".", 1)[0] + ".SelectColumns"
return from_java(java_stage, module_name)