Last day of quarter

Is there a way to natively select the last day of each quarter in PySpark? For example, in a df containing two columns - yyyy_mm_dd and sum. How could I return sum for the last day of each quarter? For the current / in progress quarter it would be good to show the max date instead.

I looked at this solution Get First Date and Last Date of Current Quarter in Python? and it works, however I was wondering if there is a solution using PySpark syntax rather than a udf?

Using a similar approach as in this answer:

df2 = df.withColumn(
    'last_day',
    F.expr("""
        to_date(
            date_trunc('quarter', to_date(input_date) + interval 3 months)
        ) - interval 1 day
    """)
)

df2.show()
+----------+----------+
|input_date|  last_day|
+----------+----------+
|2020-01-21|2020-03-31|
|2020-02-06|2020-03-31|
|2020-04-15|2020-06-30|
|2020-07-10|2020-09-30|
|2020-10-20|2020-12-31|
|2021-02-04|2021-03-31|
+----------+----------+

Then you can filter the rows where input_date == last_day

Edit: I might have misunderstood the question. You can try this approach using group by on the quarter and selecting the last row in each quarter:

from pyspark.sql import functions as F, Window

df2 = df.withColumn(
    'rn', 
    F.row_number().over(Window.partitionBy(F.year('input_date'), F.quarter('input_date')).orderBy(F.desc('input_date')))
)

df2.show()
+----------+---+
|input_date| rn|
+----------+---+
|2021-02-04|  1|
|2020-10-20|  1|
|2020-07-10|  1|
|2020-02-06|  1|
|2020-01-21|  2|
|2020-04-15|  1|
+----------+---+

And filter the rows with rn = 1, which should be the last day in each quarter.