Convert List to Spark Data Frame in Python / Spark

2019-07-10 pythonspark-2-xspark-dataframe

In Spark, SparkContext.parallelize function can be used to convert list of objects to RDD and then RDD can be converted to DataFrame object through SparkSession.

In PySpark, we can convert a Python list to RDD using SparkContext.parallelize function.

+----------+-----+------------------+|  Category|Count|       Description|+----------+-----+------------------+|Category A|  100|This is category A||Category B|  120|This is category B||Category C|  150|This is category C|+----------+-----+------------------+

Code snippet

from pyspark.sql import SparkSession
from pyspark.sql.types import ArrayType, StructField, StructType, StringType, IntegerType, DecimalType
from decimal import Decimal

appName = "PySpark Example - Python Array/List to Spark Data Frame"
master = "local"

# Create Spark session
spark = SparkSession.builder \
    .appName(appName) \
    .master(master) \
    .getOrCreate()

# List
data = [('Category A', Decimal(100), "This is category A"),
        ('Category B', Decimal(120), "This is category B"),
        ('Category C', Decimal(150), "This is category C")]

# Create a schema for the dataframe
schema = StructType([
    StructField('Category', StringType(), True),
    StructField('Count', DecimalType(), True),
    StructField('Description', StringType(), True)
])

# Convert list to RDD
rdd = spark.sparkContext.parallelize(data)

# Create data frame
df = spark.createDataFrame(rdd,schema)
print(df.schema)
df.show()