Struct spark_connect_rs::readwriter::DataFrameReader

source · 
pub struct DataFrameReader { /* private fields */ }
Expand description

DataFrameReader represents the entrypoint to create a DataFrame from a specific file format.

Implementations§

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impl DataFrameReader

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pub fn new(spark_session: SparkSession) -> Self

Create a new DataFrameReader with a SparkSession

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pub fn format(self, format: &str) -> Self

Specifies the input data source format

Examples found in repository?
examples/reader.rs (line 16)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let path = ["/opt/spark/examples/src/main/resources/people.csv"];

    let mut df = spark
        .read()
        .format("csv")
        .option("header", "True")
        .option("delimiter", ";")
        .load(path);

    df.select([
        F::col("name"),
        F::col("age").cast("int").alias("age_int"),
        (F::lit(3.0) + F::col("age").cast("int")).alias("addition"),
    ])
    .sort(vec![F::col("name").desc()])
    .show(Some(5), None, None)
    .await?;

    // print results
    // +--------------------------+
    // | show_string              |
    // +--------------------------+
    // | +-----+-------+--------+ |
    // | |name |age_int|addition| |
    // | +-----+-------+--------+ |
    // | |Jorge|30     |33.0    | |
    // | |Bob  |32     |35.0    | |
    // | +-----+-------+--------+ |
    // |                          |
    // +--------------------------+

    Ok(())
}
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examples/writer.rs (line 33)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let df = spark
        .clone()
        .range(None, 1000, 1, Some(16))
        .select(col("id").alias("range_id"));

    let path = "/opt/spark/examples/src/main/rust/employees/";

    df.write()
        .format("csv")
        .mode(SaveMode::Overwrite)
        .option("header", "true")
        .save(path)
        .await?;

    let mut df = spark
        .clone()
        .read()
        .format("csv")
        .option("header", "true")
        .load([path]);

    df.show(Some(10), None, None).await?;

    // print results may slighty vary but should be close to the below
    // +--------------------------+
    // | show_string              |
    // +--------------------------+
    // | +--------+               |
    // | |range_id|               |
    // | +--------+               |
    // | |312     |               |
    // | |313     |               |
    // | |314     |               |
    // | |315     |               |
    // | |316     |               |
    // | |317     |               |
    // | |318     |               |
    // | |319     |               |
    // | |320     |               |
    // | |321     |               |
    // | +--------+               |
    // | only showing top 10 rows |
    // |                          |
    // +--------------------------+

    Ok(())
}
examples/delta.rs (line 22)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let paths = ["/opt/spark/examples/src/main/resources/people.csv"];

    let df = spark
        .clone()
        .read()
        .format("csv")
        .option("header", "True")
        .option("delimiter", ";")
        .option("inferSchema", "True")
        .load(paths);

    df.write()
        .format("delta")
        .mode(SaveMode::Overwrite)
        .saveAsTable("default.people_delta")
        .await
        .unwrap();

    spark
        .sql("DESCRIBE HISTORY default.people_delta")
        .await?
        .show(Some(1), None, Some(true))
        .await
        .unwrap();

    // print results
    // +-------------------------------------------------------------------------------------------------------+
    // | show_string                                                                                           |
    // +-------------------------------------------------------------------------------------------------------+
    // | -RECORD 0-------------------------------------------------------------------------------------------- |
    // |  version             | 3                                                                              |
    // |  timestamp           | 2024-03-16 13:46:23.552                                                        |
    // |  userId              | NULL                                                                           |
    // |  userName            | NULL                                                                           |
    // |  operation           | CREATE OR REPLACE TABLE AS SELECT                                              |
    // |  operationParameters | {isManaged -> true, description -> NULL, partitionBy -> [], properties -> {}}  |
    // |  job                 | NULL                                                                           |
    // |  notebook            | NULL                                                                           |
    // |  clusterId           | NULL                                                                           |
    // |  readVersion         | 2                                                                              |
    // |  isolationLevel      | Serializable                                                                   |
    // |  isBlindAppend       | false                                                                          |
    // |  operationMetrics    | {numFiles -> 1, numOutputRows -> 2, numOutputBytes -> 988}                     |
    // |  userMetadata        | NULL                                                                           |
    // |  engineInfo          | Apache-Spark/3.5.0 Delta-Lake/3.0.0                                            |
    // | only showing top 1 row                                                                                |
    // |                                                                                                       |
    // +-------------------------------------------------------------------------------------------------------+

    Ok(())
}
source

pub fn option(self, key: &str, value: &str) -> Self

Add an input option for the underlying data source

Examples found in repository?
examples/reader.rs (line 17)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let path = ["/opt/spark/examples/src/main/resources/people.csv"];

    let mut df = spark
        .read()
        .format("csv")
        .option("header", "True")
        .option("delimiter", ";")
        .load(path);

    df.select([
        F::col("name"),
        F::col("age").cast("int").alias("age_int"),
        (F::lit(3.0) + F::col("age").cast("int")).alias("addition"),
    ])
    .sort(vec![F::col("name").desc()])
    .show(Some(5), None, None)
    .await?;

    // print results
    // +--------------------------+
    // | show_string              |
    // +--------------------------+
    // | +-----+-------+--------+ |
    // | |name |age_int|addition| |
    // | +-----+-------+--------+ |
    // | |Jorge|30     |33.0    | |
    // | |Bob  |32     |35.0    | |
    // | +-----+-------+--------+ |
    // |                          |
    // +--------------------------+

    Ok(())
}
More examples
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examples/writer.rs (line 34)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let df = spark
        .clone()
        .range(None, 1000, 1, Some(16))
        .select(col("id").alias("range_id"));

    let path = "/opt/spark/examples/src/main/rust/employees/";

    df.write()
        .format("csv")
        .mode(SaveMode::Overwrite)
        .option("header", "true")
        .save(path)
        .await?;

    let mut df = spark
        .clone()
        .read()
        .format("csv")
        .option("header", "true")
        .load([path]);

    df.show(Some(10), None, None).await?;

    // print results may slighty vary but should be close to the below
    // +--------------------------+
    // | show_string              |
    // +--------------------------+
    // | +--------+               |
    // | |range_id|               |
    // | +--------+               |
    // | |312     |               |
    // | |313     |               |
    // | |314     |               |
    // | |315     |               |
    // | |316     |               |
    // | |317     |               |
    // | |318     |               |
    // | |319     |               |
    // | |320     |               |
    // | |321     |               |
    // | +--------+               |
    // | only showing top 10 rows |
    // |                          |
    // +--------------------------+

    Ok(())
}
examples/delta.rs (line 23)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let paths = ["/opt/spark/examples/src/main/resources/people.csv"];

    let df = spark
        .clone()
        .read()
        .format("csv")
        .option("header", "True")
        .option("delimiter", ";")
        .option("inferSchema", "True")
        .load(paths);

    df.write()
        .format("delta")
        .mode(SaveMode::Overwrite)
        .saveAsTable("default.people_delta")
        .await
        .unwrap();

    spark
        .sql("DESCRIBE HISTORY default.people_delta")
        .await?
        .show(Some(1), None, Some(true))
        .await
        .unwrap();

    // print results
    // +-------------------------------------------------------------------------------------------------------+
    // | show_string                                                                                           |
    // +-------------------------------------------------------------------------------------------------------+
    // | -RECORD 0-------------------------------------------------------------------------------------------- |
    // |  version             | 3                                                                              |
    // |  timestamp           | 2024-03-16 13:46:23.552                                                        |
    // |  userId              | NULL                                                                           |
    // |  userName            | NULL                                                                           |
    // |  operation           | CREATE OR REPLACE TABLE AS SELECT                                              |
    // |  operationParameters | {isManaged -> true, description -> NULL, partitionBy -> [], properties -> {}}  |
    // |  job                 | NULL                                                                           |
    // |  notebook            | NULL                                                                           |
    // |  clusterId           | NULL                                                                           |
    // |  readVersion         | 2                                                                              |
    // |  isolationLevel      | Serializable                                                                   |
    // |  isBlindAppend       | false                                                                          |
    // |  operationMetrics    | {numFiles -> 1, numOutputRows -> 2, numOutputBytes -> 988}                     |
    // |  userMetadata        | NULL                                                                           |
    // |  engineInfo          | Apache-Spark/3.5.0 Delta-Lake/3.0.0                                            |
    // | only showing top 1 row                                                                                |
    // |                                                                                                       |
    // +-------------------------------------------------------------------------------------------------------+

    Ok(())
}
source

pub fn options<I, K, V>(self, options: I) -> Self
where I: IntoIterator<Item = (K, V)>, K: AsRef<str>, V: AsRef<str>,

Set many input options based on an iterator of (key/value pairs) for the underlying data source

source

pub fn load<'a, I>(&mut self, paths: I) -> DataFrame
where I: IntoIterator<Item = &'a str>,

Loads data from a data source and returns it as a DataFrame

Example:

let path = vec!["some/dir/path/on/the/remote/cluster/"];

// returns a DataFrame from a csv file with a header from a the specific path
let mut df = spark.read().format("csv").option("header", "true").load(path);
Examples found in repository?
examples/reader.rs (line 19)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let path = ["/opt/spark/examples/src/main/resources/people.csv"];

    let mut df = spark
        .read()
        .format("csv")
        .option("header", "True")
        .option("delimiter", ";")
        .load(path);

    df.select([
        F::col("name"),
        F::col("age").cast("int").alias("age_int"),
        (F::lit(3.0) + F::col("age").cast("int")).alias("addition"),
    ])
    .sort(vec![F::col("name").desc()])
    .show(Some(5), None, None)
    .await?;

    // print results
    // +--------------------------+
    // | show_string              |
    // +--------------------------+
    // | +-----+-------+--------+ |
    // | |name |age_int|addition| |
    // | +-----+-------+--------+ |
    // | |Jorge|30     |33.0    | |
    // | |Bob  |32     |35.0    | |
    // | +-----+-------+--------+ |
    // |                          |
    // +--------------------------+

    Ok(())
}
More examples
Hide additional examples
examples/writer.rs (line 35)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let df = spark
        .clone()
        .range(None, 1000, 1, Some(16))
        .select(col("id").alias("range_id"));

    let path = "/opt/spark/examples/src/main/rust/employees/";

    df.write()
        .format("csv")
        .mode(SaveMode::Overwrite)
        .option("header", "true")
        .save(path)
        .await?;

    let mut df = spark
        .clone()
        .read()
        .format("csv")
        .option("header", "true")
        .load([path]);

    df.show(Some(10), None, None).await?;

    // print results may slighty vary but should be close to the below
    // +--------------------------+
    // | show_string              |
    // +--------------------------+
    // | +--------+               |
    // | |range_id|               |
    // | +--------+               |
    // | |312     |               |
    // | |313     |               |
    // | |314     |               |
    // | |315     |               |
    // | |316     |               |
    // | |317     |               |
    // | |318     |               |
    // | |319     |               |
    // | |320     |               |
    // | |321     |               |
    // | +--------+               |
    // | only showing top 10 rows |
    // |                          |
    // +--------------------------+

    Ok(())
}
examples/delta.rs (line 26)
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut spark: SparkSession = SparkSessionBuilder::default().build().await?;

    let paths = ["/opt/spark/examples/src/main/resources/people.csv"];

    let df = spark
        .clone()
        .read()
        .format("csv")
        .option("header", "True")
        .option("delimiter", ";")
        .option("inferSchema", "True")
        .load(paths);

    df.write()
        .format("delta")
        .mode(SaveMode::Overwrite)
        .saveAsTable("default.people_delta")
        .await
        .unwrap();

    spark
        .sql("DESCRIBE HISTORY default.people_delta")
        .await?
        .show(Some(1), None, Some(true))
        .await
        .unwrap();

    // print results
    // +-------------------------------------------------------------------------------------------------------+
    // | show_string                                                                                           |
    // +-------------------------------------------------------------------------------------------------------+
    // | -RECORD 0-------------------------------------------------------------------------------------------- |
    // |  version             | 3                                                                              |
    // |  timestamp           | 2024-03-16 13:46:23.552                                                        |
    // |  userId              | NULL                                                                           |
    // |  userName            | NULL                                                                           |
    // |  operation           | CREATE OR REPLACE TABLE AS SELECT                                              |
    // |  operationParameters | {isManaged -> true, description -> NULL, partitionBy -> [], properties -> {}}  |
    // |  job                 | NULL                                                                           |
    // |  notebook            | NULL                                                                           |
    // |  clusterId           | NULL                                                                           |
    // |  readVersion         | 2                                                                              |
    // |  isolationLevel      | Serializable                                                                   |
    // |  isBlindAppend       | false                                                                          |
    // |  operationMetrics    | {numFiles -> 1, numOutputRows -> 2, numOutputBytes -> 988}                     |
    // |  userMetadata        | NULL                                                                           |
    // |  engineInfo          | Apache-Spark/3.5.0 Delta-Lake/3.0.0                                            |
    // | only showing top 1 row                                                                                |
    // |                                                                                                       |
    // +-------------------------------------------------------------------------------------------------------+

    Ok(())
}
source

pub fn table( &mut self, table_name: &str, options: Option<HashMap<String, String>> ) -> DataFrame

Returns the specific table as a DataFrame

§Arguments:
  • table_name: &str of the table name
  • options: (optional Hashmap) contains additional read options for a table

Trait Implementations§

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impl Clone for DataFrameReader

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fn clone(&self) -> DataFrameReader

Returns a copy of the value. Read more
1.0.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for DataFrameReader

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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fn from(t: T) -> T

Returns the argument unchanged.

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where T: Clone,

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fn from_ref(input: &T) -> T

Converts to this type from a reference to the input type.
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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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where T: Clone,

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type Owned = T

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Creates owned data from borrowed data, usually by cloning. Read more
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Uses borrowed data to replace owned data, usually by cloning. Read more
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where U: Into<T>,

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type Error = Infallible

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Performs the conversion.
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where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

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where V: MultiLane<T>,

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where S: Into<Dispatch>,

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