pyspark.SparkContext.hadoopFile¶
-
SparkContext.
hadoopFile
(path: str, inputFormatClass: str, keyClass: str, valueClass: str, keyConverter: Optional[str] = None, valueConverter: Optional[str] = None, conf: Optional[Dict[str, str]] = None, batchSize: int = 0) → pyspark.rdd.RDD[Tuple[T, U]][source]¶ Read an ‘old’ Hadoop InputFormat with arbitrary key and value class from HDFS, a local file system (available on all nodes), or any Hadoop-supported file system URI. The mechanism is the same as for meth:SparkContext.sequenceFile.
New in version 1.1.0.
A Hadoop configuration can be passed in as a Python dict. This will be converted into a Configuration in Java.
- Parameters
- pathstr
path to Hadoop file
- inputFormatClassstr
fully qualified classname of Hadoop InputFormat (e.g. “org.apache.hadoop.mapreduce.lib.input.TextInputFormat”)
- keyClassstr
fully qualified classname of key Writable class (e.g. “org.apache.hadoop.io.Text”)
- valueClassstr
fully qualified classname of value Writable class (e.g. “org.apache.hadoop.io.LongWritable”)
- keyConverterstr, optional
fully qualified name of a function returning key WritableConverter
- valueConverterstr, optional
fully qualified name of a function returning value WritableConverter
- confdict, optional
Hadoop configuration, passed in as a dict
- batchSizeint, optional, default 0
The number of Python objects represented as a single Java object. (default 0, choose batchSize automatically)
- Returns
RDD
RDD of tuples of key and corresponding value
See also
Examples
>>> import os >>> import tempfile
Set the related classes
>>> output_format_class = "org.apache.hadoop.mapred.TextOutputFormat" >>> input_format_class = "org.apache.hadoop.mapred.TextInputFormat" >>> key_class = "org.apache.hadoop.io.IntWritable" >>> value_class = "org.apache.hadoop.io.Text"
>>> with tempfile.TemporaryDirectory() as d: ... path = os.path.join(d, "old_hadoop_file") ... ... # Write a temporary Hadoop file ... rdd = sc.parallelize([(1, ""), (1, "a"), (3, "x")]) ... rdd.saveAsHadoopFile(path, output_format_class, key_class, value_class) ... ... loaded = sc.hadoopFile(path, input_format_class, key_class, value_class) ... collected = sorted(loaded.collect())
>>> collected [(0, '1\t'), (0, '1\ta'), (0, '3\tx')]