xuyang1706 commented on a change in pull request #9355: [FLINK-13577][ml] Add an util class to build result row and generate … URL: https://github.com/apache/flink/pull/9355#discussion_r332347441
########## File path: flink-ml-parent/flink-ml-lib/src/main/java/org/apache/flink/ml/common/utils/OutputColsHelper.java ########## @@ -0,0 +1,190 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.flink.ml.common.utils; + +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.table.api.TableSchema; +import org.apache.flink.types.Row; + +import org.apache.commons.lang3.ArrayUtils; + +import java.io.Serializable; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.HashSet; + +/** + * Util for generating output schema. + * + * <p>Need following information: + * 1) data schema + * 2) output column names + * 3) output column types + * 4) keep column names + * + * <p>The following roles are followed: + * 1)If reserved columns is null, then reserve all columns from the origin dataSet. + * 2)If some of the reserved column names are the same as output column names, then they are Review comment: > Hi @xuyang1706, I read the javadoc again and I think I have some confusion on what you are trying to achieve. please kindly take a look at my comments and see if you can provide some examples in test to better clarify? thanks -Rong Thanks @walterddr, I have refined the javadoc with an example, and hope that it could make things clear. Further more, I’d like to give 3 use cases following your example. Input data schema : ` ["a":INT, "b":INT, "c":BOOL, “d”:DOUBLE]` Input data values: ``` {{1,3,true,1.0}, {2,4,false,3.0}, {3,5,false,5.0}} ``` Apply this operator: ``` new MinMaxScaler() .setSelectedCols("a","b","d") .setOutputCols("a_std","b_std","d_std"); ``` For operator MinMaxScaler’s result types are DOUBLE, and if not defined reserved Column Names, it will reserve all the original input data cols. output data schema : ` ["a":INT, "b":INT, "c":BOOL, “d”:DOUBLE, “a_std”:DOUBLE, “b_std”:DOUBLE, “d_std”:DOUBLE]` output data values: ``` {{1,3,true,1.0, 0.0,0.0,0.0}, {2,4,false,3.0, 0.5,0.5,0.5}, {3,5,false,5.0, 1.0,1.0,1.0}} ``` Apply this operator for the origin input data ``` new MinMaxScaler() .setSelectedCols("a","b","d"); ``` For operator MinMaxScaler’s result types are DOUBLE, and if not defined the output column names, it will use the selected operating columns to save the results, and changed the according column types. output data schema : ` [“a”:DOUBLE, “b”:DOUBLE, "c":BOOL, “d”:DOUBLE]` output data values: ``` {{0.0,0.0,true,0.0}, {0.5,0.5,false,0.5}, {1.0,1.0,false,1.0}} ``` Apply this operator for the origin input data ``` new LogisticRegressionModel() .setFeatureCols("a","b","c","d") .setPredictionCol("pred") .setReservedCols("a", “d”); ``` The prediction result type is decided by the model, e.g. BOOL type. output data schema : `["a":INT, “d”:DOUBLE, “pred”:BOOL]` output data values: ``` {{1,1.0,false}, {2,3.0,true}, {3,5.0,false}} ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
