Read using a filter

Read the most recent value in a given column using a filter.

Documentation pages that include this code sample

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Code sample

C#

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

Console.WriteLine("Read all rows using streaming");
// stream the content of the whole table. Apply a filter to return latest only cell values accross all rows.
ReadRowsStream responseRead = bigtableClient.ReadRows(tableName, filter: filter);

Task printRead = PrintReadRowsAsync();
printRead.Wait();

async Task PrintReadRowsAsync()
{
    var responseEnumerator = responseRead.GetAsyncEnumerator(default);
    while (await responseEnumerator.MoveNextAsync())
    {
        Row row = responseEnumerator.Current;
        Console.WriteLine(
            $"\tRow key: {row.Key.ToStringUtf8()} " +
            $"  -- Value: {row.Families[0].Columns[0].Cells[0].Value.ToStringUtf8(),-16} " +
            $"  -- Time Stamp: {row.Families[0].Columns[0].Cells[0].TimestampMicros}");
    }
}

C++

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

for (StatusOr<cbt::Row> const& row : table.ReadRows(
         cbt::RowRange::InfiniteRange(), cbt::Filter::PassAllFilter())) {
  if (!row) throw std::runtime_error(row.status().message());
  std::cout << row->row_key() << ":\n";
  for (cbt::Cell const& c : row->cells()) {
    std::cout << "\t" << c.family_name() << ":" << c.column_qualifier()
              << "    @ " << c.timestamp().count() << "us\n"
              << "\t\"" << c.value() << '"' << "\n";
  }
}

Node.js

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

console.log('Reading the entire table');
// Note: For improved performance in production applications, call
// `Table#readStream` to get a stream of rows. See the API documentation:
// https://cloud.google.com/nodejs/docs/reference/bigtable/latest/Table#createReadStream
const [allRows] = await table.getRows({filter});
for (const row of allRows) {
  console.log(`\tRead: ${getRowGreeting(row)}`);
}

Python

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

print('Scanning for all greetings:')
partial_rows = table.read_rows(filter_=row_filter)

for row in partial_rows:
    cell = row.cells[column_family_id][column][0]
    print(cell.value.decode('utf-8'))

Ruby

To learn how to install and use the client library for Bigtable, see Bigtable client libraries.

puts "Reading the entire table"
table.read_rows.each do |row|
  puts "Row key: #{row.key}, Value: #{row.cells[column_family].first.value}"
end

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