使用过滤条件进行读取

使用过滤条件读取行。

深入探索

如需查看包含此代码示例的详细文档，请参阅以下内容：

• 读取示例

代码示例

C++

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

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

namespace cbt = ::google::cloud::bigtable;
using ::google::cloud::StatusOr;
[](cbt::Table table) {
  // Read and print the rows.
  for (StatusOr<cbt::Row>& row :
       table.ReadRows(cbt::RowRange::InfiniteRange(),
                      cbt::Filter::ValueRegex("PQ2A.*"))) {
    if (!row) throw std::move(row).status();
    PrintRow(*row);
  }
}

C#

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

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

/// <summary>
/// /// Reads using a 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 async Task<string> ReadFilter(string projectId = "YOUR-PROJECT-ID", string instanceId = "YOUR-INSTANCE-ID", string tableId = "YOUR-TABLE-ID")
{
    BigtableClient bigtableClient = BigtableClient.Create();
    TableName tableName = new TableName(projectId, instanceId, tableId);

    RowFilter filter = RowFilters.ValueRegex("PQ2A.*");

    ReadRowsStream readRowsStream = bigtableClient.ReadRows(tableName, filter: filter);
    string result = "";
    await foreach (var row in readRowsStream)
    {
        result += PrintRow(row);
    }

    return result;
}

Go

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

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

func readFilter(w io.Writer, projectID, instanceID string, tableName string) error {
	// projectID := "my-project-id"
	// instanceID := "my-instance-id"
	// tableName := "mobile-time-series"

	ctx := context.Background()
	client, err := bigtable.NewClient(ctx, projectID, instanceID)
	if err != nil {
		return fmt.Errorf("bigtable.NewClient: %w", err)
	}
	defer client.Close()

	tbl := client.Open(tableName)
	err = tbl.ReadRows(ctx, bigtable.RowRange{},
		func(row bigtable.Row) bool {
			printRow(w, row)
			return true
		},
		bigtable.RowFilter(bigtable.ValueFilter("PQ2A.*$")),
	)
	if err != nil {
		return fmt.Errorf("tbl.ReadRows: %w", err)
	}

	return nil
}

Java

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

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

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

public static void readFilter(String projectId, String instanceId, String tableId) {
  Filters.Filter filter = FILTERS.value().regex("PQ2A.*");

  // Initialize client that will be used to send requests. This client only needs to be created
  // once, and can be reused for multiple requests. After completing all of your requests, call
  // the "close" method on the client to safely clean up any remaining background resources.
  try (BigtableDataClient dataClient = BigtableDataClient.create(projectId, instanceId)) {
    Query query = Query.create(TableId.of(tableId)).filter(filter);
    ServerStream<Row> rows = dataClient.readRows(query);
    for (Row row : rows) {
      printRow(row);
    }
  } catch (IOException e) {
    System.out.println(
        "Unable to initialize service client, as a network error occurred: \n" + e.toString());
  }
}

Node.js

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

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

const filter = {
  value: /PQ2A.*$/,
};

await table
  .createReadStream({
    filter,
  })
  .on('error', err => {
    // Handle the error.
    console.log(err);
  })
  .on('data', row => printRow(row.id, row.data))
  .on('end', () => {
    // All rows retrieved.
  });

PHP

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

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

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

/**
 * Read using a filter
 *
 * @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 read_filter(
    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);

    $rowFilter = Filter::value()->regex('PQ2A.*$');

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

    foreach ($rows as $key => $row) {
        print_row($key, $row);
    }
}

Python

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

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

def read_filter(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.ValueRegexFilter(b"PQ2A.*$"))
    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。

如需向 Bigtable 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。

# instance_id = "my-instance"
# table_id    = "my-table"
bigtable = Google::Cloud::Bigtable.new
table = bigtable.table instance_id, table_id

filter = Google::Cloud::Bigtable::RowFilter.value "PQ2A.*$"
table.read_rows(filter: filter).each do |row|
  print_row row
end

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。