Limit cells per column

Creates a limiting filter on cells per column.

Explore further

For detailed documentation that includes this code sample, see the following:

• Use filters

Code sample

C++

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

namespace cbt = ::google::cloud::bigtable;
using ::google::cloud::StatusOr;
[](cbt::Table table) {
  // Filter the results, only include limited cells
  cbt::Filter filter = cbt::Filter::Latest(2);
  // Read and print the rows.
  for (StatusOr<cbt::Row>& row :
       table.ReadRows(cbt::RowSet(cbt::RowRange::InfiniteRange()), filter)) {
    if (!row) throw std::move(row).status();
    std::cout << row->row_key() << " = ";
    for (auto const& cell : row->cells()) {
      std::cout << "[" << cell.family_name() << ", "
                << cell.column_qualifier() << ", " << cell.value() << "],";
    }
    std::cout << "\n";
  }
}

C#

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

/// <summary>
/// /// Read using a cells per column filter from an existing table.
///</summary>
/// <param name="projectId">Your Google Cloud Project ID.</param>
/// <param name="instanceId">Your Google Cloud Bigtable Instance ID.</param>
/// <param name="tableId">Your Google Cloud Bigtable table ID.</param>

public Task<string> FilterLimitCellsPerCol(string projectId = "YOUR-PROJECT-ID", string instanceId = "YOUR-INSTANCE-ID", string tableId = "YOUR-TABLE-ID")
{
    // A filter that matches only the most recent 2 cells within each column
    RowFilter filter = RowFilters.CellsPerColumnLimit(2);
    return ReadFilter(projectId, instanceId, tableId, filter);
}

Go

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

func filterLimitCellsPerCol(w io.Writer, projectID, instanceID string, tableName string) error {
	filter := bigtable.LatestNFilter(2)
	return readWithFilter(w, projectID, instanceID, tableName, filter)
}

Java

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

public static void filterLimitCellsPerCol() {
  // TODO(developer): Replace these variables before running the sample.
  String projectId = "my-project-id";
  String instanceId = "my-instance-id";
  String tableId = "mobile-time-series";
  filterLimitCellsPerCol(projectId, instanceId, tableId);
}

public static void filterLimitCellsPerCol(String projectId, String instanceId, String tableId) {
  // A filter that matches only the most recent 2 cells within each column
  Filter filter = FILTERS.limit().cellsPerColumn(2);
  readFilter(projectId, instanceId, tableId, filter);
}

Node.js

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

const filter = {
  column: {
    cellLimit: 2,
  },
};
readWithFilter(filter);

PHP

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

use Google\Cloud\Bigtable\BigtableClient;
use Google\Cloud\Bigtable\Filter;

/**
 * Create a limiting filter on cells per column
 *
 * @param string $projectId The Google Cloud project ID
 * @param string $instanceId The ID of the Bigtable instance
 * @param string $tableId The ID of the table to read from
 */
function filter_limit_cells_per_col(
    string $projectId,
    string $instanceId,
    string $tableId
): void {
    // Connect to an existing table with an existing instance.
    $dataClient = new BigtableClient([
        'projectId' => $projectId,
    ]);
    $table = $dataClient->table($instanceId, $tableId);

    $filter = Filter::limit()->cellsPerColumn(2);

    $rows = $table->readRows([
        'filter' => $filter
    ]);

    foreach ($rows as $key => $row) {
        // The "print_row" helper function is defined in https://cloud.google.com/bigtable/docs/samples/bigtable-reads-print
        print_row($key, $row);
    }
}

Python

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

def filter_limit_cells_per_col(project_id, instance_id, table_id):
    from google.cloud import bigtable
    from google.cloud.bigtable import row_filters

    client = bigtable.Client(project=project_id, admin=True)
    instance = client.instance(instance_id)
    table = instance.table(table_id)

    rows = table.read_rows(filter_=row_filters.CellsColumnLimitFilter(2))
    for row in rows:
        print_row(row)

Ruby

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

To authenticate to Bigtable, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

# instance_id = "my-instance"
# table_id    = "my-table"
filter = Google::Cloud::Bigtable::RowFilter.cells_per_column 2
read_with_filter instance_id, table_id, filter

What's next

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