使用条件过滤条件进行读取

使用条件创建复合过滤条件。

包含此代码示例的文档页面

如需查看上下文中使用的代码示例,请参阅以下文档:

代码示例

C#

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

/// <summary>
/// /// Read using a conditional 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 string filterComposingCondition(string projectId = "YOUR-PROJECT-ID", string instanceId = "YOUR-INSTANCE-ID", string tableId = "YOUR-TABLE-ID")
{
    // A filter that applies the label passed-filter IF the cell has the column qualifier
    // data_plan_10gb AND the value true, OTHERWISE applies the label filtered-out
    RowFilter filter = RowFilters.Condition(
        RowFilters.Chain(RowFilters.ColumnQualifierExact("data_plan_10gb"), RowFilters.ValueExact("true")),
        new RowFilter { ApplyLabelTransformer = "passed-filter" },
        new RowFilter { ApplyLabelTransformer = "filtered-out" }
        );
    return readFilter(projectId, instanceId, tableId, filter);
}

C++

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

namespace cbt = ::google::cloud::bigtable;
using ::google::cloud::StatusOr;
[](cbt::Table table) {
  cbt::Filter filter = cbt::Filter::Condition(
      cbt::Filter::Chain(cbt::Filter::ValueRegex("true"),
                         cbt::Filter::ColumnRegex("data_plan_10gb")),
      cbt::Filter::ApplyLabelTransformer("passed-filter"),
      cbt::Filter::ApplyLabelTransformer("filtered-out"));
  // Read and print the rows.
  for (StatusOr<cbt::Row> const& row :
       table.ReadRows(cbt::RowSet(cbt::RowRange::InfiniteRange()), filter)) {
    if (!row) throw std::runtime_error(row.status().message());
    std::cout << row->row_key() << " = ";
    for (auto const& cell : row->cells()) {
      std::cout << "[" << cell.family_name() << ", "
                << cell.column_qualifier() << ", " << cell.value()
                << ", label(";
      for (auto const& label : cell.labels()) {
        std::cout << label << ",";
      }
      std::cout << ")],";
    }
    std::cout << "\n";
  }
}

Go

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

func filterComposingCondition(w io.Writer, projectID, instanceID string, tableName string) error {
	filter := bigtable.ConditionFilter(
		bigtable.ChainFilters(bigtable.ColumnFilter("data_plan_10gb"), bigtable.ValueFilter("true")),
		bigtable.StripValueFilter(),
		bigtable.PassAllFilter())
	return readWithFilter(w, projectID, instanceID, tableName, filter)
}

Java

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

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

public static void filterComposingCondition(String projectId, String instanceId, String tableId) {
  // A filter that applies the label passed-filter IF the cell has the column qualifier
  // data_plan_10gb AND the value true, OTHERWISE applies the label filtered-out
  Filter filter =
      FILTERS
          .condition(
              FILTERS
                  .chain()
                  .filter(FILTERS.qualifier().exactMatch("data_plan_10gb"))
                  .filter(FILTERS.value().exactMatch("true")))
          .then(FILTERS.label("passed-filter"))
          .otherwise(FILTERS.label("filtered-out"));
  readFilter(projectId, instanceId, tableId, filter);
}

Node.js

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

const filter = {
  condition: {
    test: [
      {column: 'data_plan_10gb'},
      {
        value: 'true',
      },
    ],
    pass: {
      label: 'passed-filter',
    },
    fail: {
      label: 'filtered-out',
    },
  },
};
readWithFilter(filter);

PHP

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

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

/**
 * Create a composite filter using a conditional
 *
 * @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_composing_condition(
    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::condition(
        Filter::chain()
            ->addFilter(Filter::value()->exactMatch(unpack('C*', 1)))
            ->addFilter(Filter::qualifier()->exactMatch('data_plan_10gb'))
    )
        ->then(Filter::label('passed-filter'))
        ->otherwise(Filter::label('filtered-out'));

    $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

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

def filter_composing_condition(project_id, instance_id, table_id):
    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.ConditionalRowFilter(
        base_filter=row_filters.RowFilterChain(filters=[
            row_filters.ColumnQualifierRegexFilter(
                "data_plan_10gb"),
            row_filters.ValueRegexFilter(
                "true")]),
        true_filter=row_filters.ApplyLabelFilter(label="passed-filter"),
        false_filter=row_filters.ApplyLabelFilter(label="filtered-out")

    ))
    for row in rows:
        print_row(row)

Ruby

如需了解如何安装和使用 Bigtable 的客户端库,请参阅 Bigtable 客户端库

# instance_id = "my-instance"
# table_id    = "my-table"
filter = Google::Cloud::Bigtable::RowFilter.condition(
  Google::Cloud::Bigtable::RowFilter.chain.qualifier("data_plan_10gb").value("true")
)
                                           .on_match(Google::Cloud::Bigtable::RowFilter.label("passed-filter"))
                                           .otherwise(Google::Cloud::Bigtable::RowFilter.label("filtered-out"))
read_with_filter instance_id, table_id, filter

后续步骤

如需搜索和过滤其他 Google Cloud 产品的代码示例,请参阅 Google Cloud 示例浏览器