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https://issues.apache.org/jira/browse/PARQUET-1196?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16362537#comment-16362537
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ASF GitHub Bot commented on PARQUET-1196:
-----------------------------------------

wesm commented on a change in pull request #436: PARQUET-1196: Example 
parquet_arrow project
URL: https://github.com/apache/parquet-cpp/pull/436#discussion_r167908530
 
 

 ##########
 File path: examples/parquet-arrow/src/reader-writer.cc
 ##########
 @@ -0,0 +1,134 @@
+// 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.
+
+#include <arrow/api.h>
+#include <arrow/io/api.h>
+#include <parquet/arrow/reader.h>
+#include <parquet/arrow/writer.h>
+#include <parquet/exception.h>
+
+// #0 Build dummy data to pass around
+// To have some input data, we first create an Arrow Table that holds
+// some data.
+std::shared_ptr<arrow::Table> generate_table() {
+  arrow::Int64Builder i64builder;
+  PARQUET_THROW_NOT_OK(i64builder.Append({1, 2, 3, 4, 5}));
+  std::shared_ptr<arrow::Array> i64array;
+  PARQUET_THROW_NOT_OK(i64builder.Finish(&i64array));
+
+  arrow::StringBuilder strbuilder;
+  PARQUET_THROW_NOT_OK(strbuilder.Append("some"));
+  PARQUET_THROW_NOT_OK(strbuilder.Append("string"));
+  PARQUET_THROW_NOT_OK(strbuilder.Append("content"));
+  PARQUET_THROW_NOT_OK(strbuilder.Append("in"));
+  PARQUET_THROW_NOT_OK(strbuilder.Append("rows"));
+  std::shared_ptr<arrow::Array> strarray;
+  PARQUET_THROW_NOT_OK(strbuilder.Finish(&strarray));
+
+  std::shared_ptr<arrow::Schema> schema = arrow::schema(
+      {arrow::field("int", arrow::int64()), arrow::field("str", 
arrow::utf8())});
+
+  return arrow::Table::Make(schema, {i64array, strarray});
+}
+
+// #1 Write out the data as a Parquet file
+void write_parquet_file(const arrow::Table& table) {
+  std::shared_ptr<arrow::io::FileOutputStream> outfile;
+  PARQUET_THROW_NOT_OK(
+      arrow::io::FileOutputStream::Open("parquet-arrow-example.parquet", 
&outfile));
+  // The last argument to the function call is the size of the RowGroup in
+  // the parquet file. Normally you would choose this to be rather large but
+  // for the example, we use a small value to have multiple RowGroups.
+  PARQUET_THROW_NOT_OK(
+      parquet::arrow::WriteTable(table, arrow::default_memory_pool(), outfile, 
3));
+}
+
+// #2: Fully read in the file
+void read_whole_file() {
+  std::cout << "Reading parquet-arrow-example.parquet at once" << std::endl;
+  std::shared_ptr<arrow::io::ReadableFile> infile;
+  PARQUET_THROW_NOT_OK(arrow::io::ReadableFile::Open(
+      "parquet-arrow-example.parquet", arrow::default_memory_pool(), &infile));
+
+  std::unique_ptr<parquet::arrow::FileReader> reader;
+  PARQUET_THROW_NOT_OK(
+      parquet::arrow::OpenFile(infile, arrow::default_memory_pool(), &reader));
+  std::shared_ptr<arrow::Table> table;
+  PARQUET_THROW_NOT_OK(reader->ReadTable(&table));
+  std::cout << "Loaded " << table->num_rows() << " rows in " << 
table->num_columns()
+            << " columns." << std::endl;
+}
+
+// #3: Read only a single RowGroup of the parquet file
+void read_single_rowgroup() {
+  std::cout << "Reading first RowGroup of parquet-arrow-example.parquet" << 
std::endl;
+  std::shared_ptr<arrow::io::ReadableFile> infile;
+  PARQUET_THROW_NOT_OK(arrow::io::ReadableFile::Open(
+      "parquet-arrow-example.parquet", arrow::default_memory_pool(), &infile));
+
+  std::unique_ptr<parquet::arrow::FileReader> reader;
+  PARQUET_THROW_NOT_OK(
+      parquet::arrow::OpenFile(infile, arrow::default_memory_pool(), &reader));
+  std::shared_ptr<arrow::Table> table;
+  PARQUET_THROW_NOT_OK(reader->RowGroup(0)->ReadTable(&table));
+  std::cout << "Loaded " << table->num_rows() << " rows in " << 
table->num_columns()
+            << " columns." << std::endl;
+}
+
+// #4: Read only a single column of the whole parquet file
+void read_single_column() {
+  std::cout << "Reading first column of parquet-arrow-example.parquet" << 
std::endl;
+  std::shared_ptr<arrow::io::ReadableFile> infile;
+  PARQUET_THROW_NOT_OK(arrow::io::ReadableFile::Open(
+      "parquet-arrow-example.parquet", arrow::default_memory_pool(), &infile));
+
+  std::unique_ptr<parquet::arrow::FileReader> reader;
+  PARQUET_THROW_NOT_OK(
+      parquet::arrow::OpenFile(infile, arrow::default_memory_pool(), &reader));
+  std::shared_ptr<arrow::Array> array;
+  PARQUET_THROW_NOT_OK(reader->ReadColumn(0, &array));
+  arrow::PrettyPrint(*array, 4, &std::cout);
+  std::cout << std::endl;
+}
+
+// #5: Read only a single column of a RowGroup (this is known as ColumnChunk)
+//     from the Parquet file.
+void read_single_column_chunk() {
+  std::cout << "Reading first ColumnChunk of the first RowGroup of "
+               "parquet-arrow-example.parquet"
+            << std::endl;
+  std::shared_ptr<arrow::io::ReadableFile> infile;
+  PARQUET_THROW_NOT_OK(arrow::io::ReadableFile::Open(
+      "parquet-arrow-example.parquet", arrow::default_memory_pool(), &infile));
+
+  std::unique_ptr<parquet::arrow::FileReader> reader;
+  PARQUET_THROW_NOT_OK(
+      parquet::arrow::OpenFile(infile, arrow::default_memory_pool(), &reader));
+  std::shared_ptr<arrow::Array> array;
+  PARQUET_THROW_NOT_OK(reader->RowGroup(0)->Column(0)->Read(&array));
+  arrow::PrettyPrint(*array, 4, &std::cout);
 
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> [C++] Provide a parquet_arrow example project incl. CMake setup
> ---------------------------------------------------------------
>
>                 Key: PARQUET-1196
>                 URL: https://issues.apache.org/jira/browse/PARQUET-1196
>             Project: Parquet
>          Issue Type: Improvement
>          Components: parquet-cpp
>            Reporter: Uwe L. Korn
>            Assignee: Uwe L. Korn
>            Priority: Major
>             Fix For: cpp-1.4.0
>
>
> Currently we only provide a simple example for the low-level interface, we 
> should also provide an example for the prefered high-level parquet_arrow 
> interface. Additionally, we should provide a CMake project that shows how to 
> use parquet as a lib. This can then also be used in CI



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