RxParquetData

Article
07/15/2019

revoscalepy.RxParquetData(file: str = None, column_info=None,
    file_system: revoscalepy.datasource.RxFileSystem.RxFileSystem = None,
    write_factors_as_indexes: bool = False)

Description

Main generator for class RxParquetData, which extends RxSparkData.

Arguments

file

Character string specifying the location of the data. e.g. “/tmp/AirlineDemoSmall.parquet”.

column_info

List of named variable information lists. Each variable information list contains one or more of the named elements given below. Currently available properties for a column information list are: type: Character string specifying the data type for the column.

Supported types are:
    ”bool” (stored as uchar),
    “integer” (stored as int32),
    “int16” (alternative to integer for smaller storage space),
    “float32” (stored as FloatType),
    “numeric” (stored as float64),
    “character” (stored as string),
    “factor” (stored as uint32),
    “Date” (stored as Date, i.e. float64.)
    “POSIXct” (stored as POSIXct, i.e. float64.)

levels: List of strings containing the levels when type = “factor”. If the levels property is not provided, factor levels will be determined by the values in the source column. If levels are provided, any value that does not match a provided level will be converted to a missing value.

file_system

Character string or RxFileSystem object indicating type of file system; It supports native HDFS and other HDFS compatible systems, e.g., Azure Blob and Azure Data Lake. Local file system is not supported.

write_factors_as_indexes

Bool, if True, when writing to an RxParquetData data source, underlying factor indexes will be written instead of the string representations.

Returns

Object of class RxParquetData.

Example

import os
from revoscalepy import rx_data_step, RxOptions, RxParquetData
sample_data_path = RxOptions.get_option("sampleDataDir")
colInfo = {"DayOfWeek": {"type":"factor"}}
ds = RxParquetData(os.path.join(sample_data_path, "AirlineDemoSmall.parquet"))
result = rx_data_step(ds)

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