I have to add column to a PySpark dataframe based on a list of values.
a= spark.createDataFrame([("Dog", "Cat"), ("Cat", "Dog"), ("Mouse", "Cat")],["Animal", "Enemy"])
I have a list called rating, which is a rating of each pet.
rating = [5,4,1]
I need to append the dataframe with a column called Rating, such that
+------+-----+------+
|Animal|Enemy|Rating|
+------+-----+------+
| Dog| Cat| 5|
| Cat| Dog| 4|
| Mouse| Cat| 1|
+------+-----+------+
I have done the following however it is returning only the first value in the list in the Rating Column
def add_labels():
return rating.pop(0)
labels_udf = udf(add_labels, IntegerType())
new_df = a.withColumn('Rating', labels_udf()).cache()
out:
+------+-----+------+
|Animal|Enemy|Rating|
+------+-----+------+
| Dog| Cat| 5|
| Cat| Dog| 5|
| Mouse| Cat| 5|
+------+-----+------+
from pyspark.sql.functions import monotonically_increasing_id, row_number
from pyspark.sql import Window
#sample data
a= sqlContext.createDataFrame([("Dog", "Cat"), ("Cat", "Dog"), ("Mouse", "Cat")],
["Animal", "Enemy"])
a.show()
#convert list to a dataframe
rating = [5,4,1]
b = sqlContext.createDataFrame([(l,) for l in rating], ['Rating'])
#add 'sequential' index and join both dataframe to get the final result
a = a.withColumn("row_idx", row_number().over(Window.orderBy(monotonically_increasing_id())))
b = b.withColumn("row_idx", row_number().over(Window.orderBy(monotonically_increasing_id())))
final_df = a.join(b, a.row_idx == b.row_idx).\
drop("row_idx")
final_df.show()
Input:
+------+-----+
|Animal|Enemy|
+------+-----+
| Dog| Cat|
| Cat| Dog|
| Mouse| Cat|
+------+-----+
Output is:
+------+-----+------+
|Animal|Enemy|Rating|
+------+-----+------+
| Cat| Dog| 4|
| Dog| Cat| 5|
| Mouse| Cat| 1|
+------+-----+------+
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With