Convert Multiple columns into a single row with a variable amount of columns - apache-spark

I have a spark dataframe containing businesses with their contact numbers in 2 columns, however some of my businesses are repeated with different contact info, for example:
Name:
Phone:
bus1
082...
bus1
087...
bus2
076...
bus3
081...
bus3
084...
bus3
086...
I want to have 3 lines, 1 for each business with varying phone numbers in each, for example:
Name:
Phone1:
Phone2:
Phone3:
bus1
082...
087...
bus2
076...
bus3
081...
084...
086...
I have tried using select('Name','Phone').distinct(), but I don't know how to pivot it to a single row matching on the 'Name' column... please help

First construct the phone array based on name, and then split the array into multiple columns.
df = df.groupBy('Name').agg(F.collect_list('Phone').alias('Phone'))
df = df.select('Name', *[F.col('Phone')[i].alias(f'Phone{str(i+1)}') for i in range(3)])
df.show(truncate=False)

Try something as below -
Input DataFrame
df = spark.createDataFrame([('bus1', '082...'), ('bus1', '087...'), ('bus2', '076...'), ('bus3', '081...'),('bus3', '084...'),('bus3', '086...')], schema=["Name", "Phone"])
df.show()
+----+------+
|Name| Phone|
+----+------+
|bus1|082...|
|bus1|087...|
|bus2|076...|
|bus3|081...|
|bus3|084...|
|bus3|086...|
+----+------+
Collecting all the Phone values into an array using collect_list
from pyspark.sql.functions import *
from pyspark.sql.types import *
df1 = df.groupBy("Name").agg(collect_list(col("Phone")).alias("Phone")).select( "Name", "Phone")
df1.show(truncate=False)
+----+------------------------+
|Name|Phone |
+----+------------------------+
|bus1|[082..., 087...] |
|bus2|[076...] |
|bus3|[081..., 084..., 086...]|
+----+------------------------+
Splitting Phone into multiple columns
df1.select(['Name'] + [df1.Phone[x].alias(f"Phone{x+1}") for x in range(0,3)]).show(truncate=False)
+----+------+------+------+
|Name|Phone1|Phone2|Phone3|
+----+------+------+------+
|bus1|082...|087...|null |
|bus2|076...|null |null |
|bus3|081...|084...|086...|
+----+------+------+------+

Related

Combine columns into list of key, value pairs (no UDF)

I'd like to create a new column that is a JSON representation of some other columns. key, value pairs in a list.
Source:
origin
destination
count
toronto
ottawa
5
montreal
vancouver
10
What I want:
origin
destination
count
json
toronto
ottawa
5
[{"origin":"toronto"},{"destination","ottawa"}, {"count": "5"}]
montreal
vancouver
10
[{"origin":"montreal"},{"destination","vancouver"}, {"count": "10"}]
(everything can be a string, doesn't matter).
I've tried something like:
df.withColumn('json', to_json(struct(col('origin'), col('destination'), col('count'))))
But it creates the column with all the key:value pairs in one object:
{"origin":"United States","destination":"Romania"}
Is this possible without a UDF?
A way to hack around this:
import pyspark.sql.functions as F
df2 = df.withColumn(
'json',
F.array(
F.to_json(F.struct('origin')),
F.to_json(F.struct('destination')),
F.to_json(F.struct('count'))
).cast('string')
)
df2.show(truncate=False)
+--------+-----------+-----+--------------------------------------------------------------------+
|origin |destination|count|json |
+--------+-----------+-----+--------------------------------------------------------------------+
|toronto |ottawa |5 |[{"origin":"toronto"}, {"destination":"ottawa"}, {"count":"5"}] |
|montreal|vancouver |10 |[{"origin":"montreal"}, {"destination":"vancouver"}, {"count":"10"}]|
+--------+-----------+-----+--------------------------------------------------------------------+
Another way by creating array of maps column before calling to_json:
from pyspark.sql import functions as F
df1 = df.withColumn(
'json',
F.to_json(F.array(*[F.create_map(F.lit(c), F.col(c)) for c in df.columns]))
)
df1.show(truncate=False)
#+--------+-----------+-----+------------------------------------------------------------------+
#|origin |destination|count|json |
#+--------+-----------+-----+------------------------------------------------------------------+
#|toronto |ottawa |5 |[{"origin":"toronto"},{"destination":"ottawa"},{"count":"5"}] |
#|montreal|vancouver |10 |[{"origin":"montreal"},{"destination":"vancouver"},{"count":"10"}]|
#+--------+-----------+-----+------------------------------------------------------------------+

How to join the two dataframe by condition in PySpark?

I am having two dataframe like described below
Dataframe 1
P_ID P_Name P_Description P_Size
100 Moto Mobile 16
200 Apple Mobile 15
300 Oppo Mobile 18
Dataframe 2
P_ID List_Code P_Amount
100 ALPHA 20000
100 BETA 60000
300 GAMMA 15000
Requirement :
Need to join the two dataframe by P_ID.
Information about the dataframe :
In dataframe 1 P_ID is a primary key and dataframe 2 does't have any primary attribute.
How to join the dataframe
Need to create new columns in dataframe 1 from the value of dataframe 2 List_Code appends with "_price". If dataframe 2 List_Code contains 20 unique values we need to create 20 column in dataframe 1. Then, we have fill the value in newly created column in dataframe 1 from the dataframe 2 P_Amount column based on P_ID if present else fills with zero. After creation of dataframe we need to join the dataframe based on the P_ID. If we add the column with the expected value in dataframe 1 we can join the dataframe. My problem is creating new columns with the expected value.
The expected dataframe is shown below
Expected dataframe
P_ID P_Name P_Description P_Size ALPHA_price BETA_price GAMMA_price
100 Moto Mobile 16 20000 60000 0
200 Apple Mobile 15 0 0 0
300 Oppo Mobile 18 0 0 15000
Can you please help me to solve the problem, thanks in advance.
For you application, you need to pivot the second dataframe and then join the first dataframe on to the pivoted result on P_ID using left join.
See the code below.
df_1 = pd.DataFrame({'P_ID' : [100, 200, 300], 'P_Name': ['Moto', 'Apple', 'Oppo'], 'P_Size' : [16, 15, 18]})
sdf_1 = sc.createDataFrame(df_1)
df_2 = pd.DataFrame({'P_ID' : [100, 100, 300], 'List_Code': ['ALPHA', 'BETA', 'GAMMA'], 'P_Amount' : [20000, 60000, 10000]})
sdf_2 = sc.createDataFrame(df_2)
sdf_pivoted = sdf_2.groupby('P_ID').pivot('List_Code').agg(f.sum('P_Amount')).fillna(0)
sdf_joined = sdf_1.join(sdf_pivoted, on='P_ID', how='left').fillna(0)
sdf_joined.show()
+----+------+------+-----+-----+-----+
|P_ID|P_Name|P_Size|ALPHA| BETA|GAMMA|
+----+------+------+-----+-----+-----+
| 300| Oppo| 18| 0| 0|10000|
| 200| Apple| 15| 0| 0| 0|
| 100| Moto| 16|20000|60000| 0|
+----+------+------+-----+-----+-----+
You can change the column names or ordering of the dataframe as needed.

How to iterate over columns of "spark" dataframe?

I have the following Spark dataframe that is created dynamically
| name| number |
+--------+---------+
| Andy | (20,10,30)|
|Berta | (30,40,20)|
| Joe | (40,90,60)|
+-------+---------+
Now, I need to iterate each row and column in Spark to print the following output, How to do this?
Andy 20
Andy 10
Andy 30
Berta 30
Berta 40
Berta 20
Joe 40
Joe 90
Joe 60
Assuming the number column is of string Data Type, you can achieve the desired results by following below steps.
Original Data Frame:
val df = Seq(("Andy", "20,10,30"), ("Berta", "30,40,20"), ("Joe", "40,90,60"))
.toDF("name", "number")
Then Create an intermediate Data Frame having 3 number columns by splitting the number column with comma.
val Interim_Df = df.withColumn("n1", split(col("number"), ",").getItem(0))
.withColumn("n2", split(col("number"), ",").getItem(1))
.withColumn("n3", split(col("number"), ",").getItem(2))
.drop("number")
Then generate the final result data frame by doing union with oneIndexDfs.
val columnIndexes = Seq(1, 2, 3)
val onlyOneIndexDfs = columnIndexes.map(x =>
Interim_Df.select(
$"name",
col(s"n$x").alias("number")))
val resultDF = onlyOneIndexDfs.reduce(_ union _)
You need explode function.
Here samples of its usage.

Python Spark: How to join 2 datasets containing >2 elements for each tuple

I'm trying to join data from these two datasets, based on the common "stock" key
stock, sector
GOOG Tech
stock, date, volume
GOOG 2015 5759725
The join method should join these together, however the resulting RDD I got is of the form:
GOOG, (Tech, 2015)
I'm trying to obtain:
(Tech, 2015) 5759726
Additionally, how do I go about reducing the results by the keys (e.g. (Tech, 2015)) in order to obtain a numerical summation for each sector and year?
from pyspark.sql.functions import struct, col, sum
#sample data
df1 = sc.parallelize([['GOOG', 'Tech'],
['AAPL', 'Tech'],
['XOM', 'Oil']]).toDF(["stock","sector"])
df2 = sc.parallelize([['GOOG', '2015', '5759725'],
['AAPL', '2015', '123'],
['XOM', '2015', '234'],
['XOM', '2016', '789']]).toDF(["stock","date","volume"])
#final output
df = df1.join(df2, ['stock'], 'inner').\
withColumn('sector_year', struct(col('sector'), col('date'))).\
drop('stock','sector','date')
df.show()
#numerical summation for each sector and year
df.groupBy('sector_year').agg(sum('volume')).show()
Output is:
+-------+-----------+
| volume|sector_year|
+-------+-----------+
| 123|[Tech,2015]|
| 234| [Oil,2015]|
| 789| [Oil,2016]|
|5759725|[Tech,2015]|
+-------+-----------+
+-----------+-----------+
|sector_year|sum(volume)|
+-----------+-----------+
|[Tech,2015]| 5759848.0|
| [Oil,2015]| 234.0|
| [Oil,2016]| 789.0|
+-----------+-----------+

Apache Spark - Finding Array/List/Set subsets

I have 2 dataframes each one having Array[String] as one of the columns. For each entry in one dataframe, I need to find out subsets, if any, in the other dataframe. An example is here:
DF1:
----------------------------------------------------
id : Long | labels : Array[String]
---------------------------------------------------
10 | [label1, label2, label3]
11 | [label4, label5]
12 | [label6, label7]
DF2:
----------------------------------------------------
item : String | labels : Array[String]
---------------------------------------------------
item1 | [label1, label2, label3, label4, label5]
item2 | [label4, label5]
item3 | [label4, label5, label6, label7]
After the subset operation I described, the expected o/p should be
DF3:
----------------------------------------------------
item : String | id : Long
---------------------------------------------------
item1 | [10, 11]
item2 | [11]
item3 | [11, 12]
It is guaranteed that the DF2, will always have corresponding subsets in DF1, so there won't be any left over elements.
Can someone please help with the right approach here ? It looks like for each element in DF2, I need to scan DF1 and do subset operation (or set subtraction) on the 2nd column until I find all the subsets and exhaust the labels in that row and while doing that accumulate the list of "id" fields. How do I do this in compact and efficient manner ? Any help is greatly appreciated. Realistically, I may have 100s of elements in DF1 and 1000s of elements in DF2.
I'm not aware of any way to perform this kind of operation in an efficient way. However, here is one possible solution using UDF as well as Cartesian join.
The UDF takes two sequences and checks if all strings in the first exists in the second:
val matchLabel = udf((array1: Seq[String], array2: Seq[String]) => {
array1.forall{x => array2.contains(x)}
})
To use Cartesian join, it needs to be enabled as it is computationally expensive.
val spark = SparkSession.builder.getOrCreate()
spark.conf.set("spark.sql.crossJoin.enabled", true)
The two dataframes are joined together utilizing the UDF. Afterwards the resulting dataframe is grouped by the item column to collect a list of all ids. Using the same DF1 and DF2 as in the question:
val DF3 = DF2.join(DF1, matchLabel(DF1("labels"), DF2("labels")))
.groupBy("item")
.agg(collect_list("id").as("id"))
The result is as follows:
+-----+--------+
| item| id|
+-----+--------+
|item3|[11, 12]|
|item2| [11]|
|item1|[10, 11]|
+-----+--------+

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