dataframescalaapache-sparkapache-spark-sql

How can I calculate the timestamp difference based on status using spark Dataframes?


I am trying to calculate the timestamp difference on cumulative rows based on ID and status columns

Example dataframe:

ID TIMESTAMP STATUS
V1 2023-06-18 13:00:00 1
V1 2023-06-18 13:01:00 1
V1 2023-06-18 13:02:00 1
V1 2023-06-18 13:03:00 1
V1 2023-06-18 13:06:00 0
V1 2023-06-18 13:07:00 0
V1 2023-06-18 13:08:00 0
V1 2023-06-18 13:09:00 1
V1 2023-06-18 13:10:00 1
V1 2023-06-18 13:11:00 1
V1 2023-06-18 13:12:00 1

The expected result should be like

ID TIMESTAMP STATUS TIMESTAMP_DIFF(in_seconds)
V1 2023-06-18 13:00:00 1 0
V1 2023-06-18 13:01:00 1 60
V1 2023-06-18 13:02:00 1 120
V1 2023-06-18 13:03:00 1 180
V1 2023-06-18 13:06:00 0 0
V1 2023-06-18 13:07:00 0 60
V1 2023-06-18 13:08:00 0 120
V1 2023-06-18 13:09:00 1 0
V1 2023-06-18 13:10:00 1 60
V1 2023-06-18 13:11:00 1 120
V1 2023-06-18 13:12:00 1 180

Solution

  • You can achieve this in PySpark using window functions. The idea is to create a group for consecutive rows with the same STATUS (partitioned by ID), then calculate the difference between the current TIMESTAMP and the first TIMESTAMP in each group.

    Here’s how you can do it:

    from pyspark.sql import SparkSession
    from pyspark.sql import functions as F
    from pyspark.sql.window import Window
    
    # Sample data
    data = [
        ("V1", "2023-06-18 13:00:00", 1),
        ("V1", "2023-06-18 13:01:00", 1),
        ("V1", "2023-06-18 13:02:00", 1),
        ("V1", "2023-06-18 13:03:00", 1),
        ("V1", "2023-06-18 13:06:00", 0),
        ("V1", "2023-06-18 13:07:00", 0),
        ("V1", "2023-06-18 13:08:00", 0),
        ("V1", "2023-06-18 13:09:00", 1),
        ("V1", "2023-06-18 13:10:00", 1),
        ("V1", "2023-06-18 13:11:00", 1),
        ("V1", "2023-06-18 13:12:00", 1),
    ]
    
    spark = SparkSession.builder.getOrCreate()
    df = spark.createDataFrame(data, ["ID", "TIMESTAMP", "STATUS"])
    
    # Convert TIMESTAMP to timestamp type
    df = df.withColumn("TIMESTAMP", F.to_timestamp("TIMESTAMP"))
    
    # Identify group for consecutive STATUS using difference of row_number
    window_id = Window.partitionBy("ID").orderBy("TIMESTAMP")
    df = df.withColumn("row_num", F.row_number().over(window_id))
    df = df.withColumn("status_change", F.when(
        F.lag("STATUS").over(window_id) != F.col("STATUS"), 1
    ).otherwise(0))
    df = df.withColumn("group", F.sum("status_change").over(window_id.rowsBetween(Window.unboundedPreceding, 0)))
    
    # Calculate the first timestamp in each group
    window_group = Window.partitionBy("ID", "group").orderBy("TIMESTAMP")
    df = df.withColumn("first_ts", F.first("TIMESTAMP").over(window_group))
    
    # Calculate the difference in seconds
    df = df.withColumn("TIMESTAMP_DIFF(in_seconds)", F.col("TIMESTAMP").cast("long") - F.col("first_ts").cast("long"))
    
    # Select final columns
    result = df.select("ID", "TIMESTAMP", "STATUS", "TIMESTAMP_DIFF(in_seconds)")
    
    result.show(truncate=False)
    

    Also, keep in mind that to use pyspark you will have to have the right version of java installed in your machine. For linux, you can use the following commands:

    sudo apt update
    sudo apt install openjdk-17-jdk
    
    export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
    export PATH=$JAVA_HOME/bin:$PATH
    
    java -version
    

    To install pyspark, use the following commands:

    pip install pyspark
    pip install pyspark[sql]
    

    The output of running the above code is the following:
    enter image description here