Date and Time Extract Functions¶

Let us get an overview about Date and Time extract functions. Here are the extract functions that are useful which are self explanatory.

year
month
weekofyear
dayofyear
dayofmonth
dayofweek
hour
minute
second

There might be few more functions. You can review based up on your requirements.

Let us start spark context for this Notebook so that we can execute the code provided. You can sign up for our 10 node state of the art cluster/labs to learn Spark SQL using our unique integrated LMS.

from pyspark.sql import SparkSession

import getpass
username = getpass.getuser()

spark = SparkSession. \
    builder. \
    config('spark.ui.port', '0'). \
    config("spark.sql.warehouse.dir", f"/user/{username}/warehouse"). \
    enableHiveSupport(). \
    appName(f'{username} | Python - Processing Column Data'). \
    master('yarn'). \
    getOrCreate()

If you are going to use CLIs, you can use Spark SQL using one of the 3 approaches.

Using Spark SQL

spark2-sql \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

Using Scala

spark2-shell \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

Using Pyspark

pyspark2 \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

l = [("X", )]

df = spark.createDataFrame(l).toDF("dummy")

df.show()

+-----+
|dummy|
+-----+
|    X|
+-----+

from pyspark.sql.functions import year, month, weekofyear, dayofmonth, \
    dayofyear, dayofweek, current_date

df.select(
    current_date().alias('current_date'), 
    year(current_date()).alias('year'),
    month(current_date()).alias('month'),
    weekofyear(current_date()).alias('weekofyear'),
    dayofyear(current_date()).alias('dayofyear'),
    dayofmonth(current_date()).alias('dayofmonth'),
    dayofweek(current_date()).alias('dayofweek')
).show() #yyyy-MM-dd

+------------+----+-----+----------+---------+----------+---------+
|current_date|year|month|weekofyear|dayofyear|dayofmonth|dayofweek|
+------------+----+-----+----------+---------+----------+---------+
|  2021-03-02|2021|    3|         9|       61|         2|        3|
+------------+----+-----+----------+---------+----------+---------+

help(dayofweek)

Help on function dayofweek in module pyspark.sql.functions:

dayofweek(col)
    Extract the day of the week of a given date as integer.
    
    >>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
    >>> df.select(dayofweek('dt').alias('day')).collect()
    [Row(day=4)]
    
    .. versionadded:: 2.3

from pyspark.sql.functions import current_timestamp, hour, minute, second

from pyspark.sql import functions

help(functions)

df.select(
    current_timestamp().alias('current_timestamp'), 
    year(current_timestamp()).alias('year'),
    month(current_timestamp()).alias('month'),
    dayofmonth(current_timestamp()).alias('dayofmonth'),
    hour(current_timestamp()).alias('hour'),
    minute(current_timestamp()).alias('minute'),
    second(current_timestamp()).alias('second')
).show(truncate=False) #yyyy-MM-dd HH:mm:ss.SSS

+-----------------------+----+-----+----------+----+------+------+
|current_timestamp      |year|month|dayofmonth|hour|minute|second|
+-----------------------+----+-----+----------+----+------+------+
|2021-03-02 14:13:53.933|2021|3    |2         |14  |13    |53    |
+-----------------------+----+-----+----------+----+------+------+

Mastering Pyspark

Date and Time Extract Functions¶