# -*- coding: utf-8 -*-
"""
Created on Sun Jun 14 10:20:19 2020

@author: prabha
"""

import pyspark
from pyspark.sql import SparkSession
from pyspark.sql.functions import approx_count_distinct,collect_list
from pyspark.sql.functions import collect_set,sum,avg,max,countDistinct,count
from pyspark.sql.functions import first, last, kurtosis, min, mean, skewness 
from pyspark.sql.functions import stddev, stddev_samp, stddev_pop, sumDistinct
from pyspark.sql.functions import variance,var_samp,  var_pop

spark = SparkSession.builder.appName('SparkByExamples.com').getOrCreate()

simpleData = [("James", "Sales", 3000),
    ("Michael", "Sales", 4600),
    ("Robert", "Sales", 4100),
    ("Maria", "Finance", 3000),
    ("James", "Sales", 3000),
    ("Scott", "Finance", 3300),
    ("Jen", "Finance", 3900),
    ("Jeff", "Marketing", 3000),
    ("Kumar", "Marketing", 2000),
    ("Saif", "Sales", 4100)
  ]
schema = ["employee_name", "department", "salary"]
  
  
df = spark.createDataFrame(data=simpleData, schema = schema)
df.printSchema()
df.show(truncate=False)

print("approx_count_distinct: " + \
      str(df.select(approx_count_distinct("salary")).collect()[0][0]))

print("avg: " + str(df.select(avg("salary")).collect()[0][0]))

df.select(collect_list("salary")).show(truncate=False)

df.select(collect_set("salary")).show(truncate=False)

df2 = df.select(countDistinct("department", "salary"))
df2.show(truncate=False)
print("Distinct Count of Department & Salary: "+str(df2.collect()[0][0]))

print("count: "+str(df.select(count("salary")).collect()[0]))
df.select(first("salary")).show(truncate=False)
df.select(last("salary")).show(truncate=False)
df.select(kurtosis("salary")).show(truncate=False)
df.select(max("salary")).show(truncate=False)
df.select(min("salary")).show(truncate=False)
df.select(mean("salary")).show(truncate=False)
df.select(skewness("salary")).show(truncate=False)
df.select(stddev("salary"), stddev_samp("salary"), \
    stddev_pop("salary")).show(truncate=False)
df.select(sum("salary")).show(truncate=False)
df.select(sumDistinct("salary")).show(truncate=False)
df.select(variance("salary"),var_samp("salary"),var_pop("salary")) \
  .show(truncate=False)