Reverse line in Apache Spark

Technical Discussions Apache Spark
#1

Suppose we have 1 TB of text data, how will I reverse the line using Apache Spark?

Input: I love to learn Apache Spark
Output: Spark Apache learn to love I

This will be easy to do using any programming language but how will I do it in Spark in an optimized way as data will be distributed among the different partitions?

#2

To reverse the lines in a large text file using Apache Spark, you can follow these steps:

  1. Load the text file as an RDD (Resilient Distributed Dataset) using the textFile method.
  2. Split each line into words using the flatMap method, and reverse the order of the words in each line using the reverse method.
  3. Group the reversed lines together using the groupBy method.
  4. Combine the reversed lines back into a single string using the reduce method.
  5. Save the reversed lines to a new file using the saveAsTextFile method.

Here’s a sample code that performs the above operations:

text_file = sc.textFile(“path/to/your/textfile.txt”)

Split each line into words, reverse the order of the words in each line, and group the reversed lines together

reversed_lines = text_file.flatMap(lambda line: line.split(" ")).map(lambda word: word[::-1]).groupBy(lambda word: 0)

Combine the reversed lines back into a single string

reversed_lines = reversed_lines.map(lambda x: " ".join(x[1]))

Save the reversed lines to a new file

reversed_lines.saveAsTextFile(“path/to/save/reversedlines”)

1 Like
#3

@Shubh_Tripathi Thanks a lot for replying, however, I didn’t understand this transformation “.groupBy(lambda word: 0)”, can you please tell me what will be resultant RDD after applying this transformation?

#4

Why don’t you try the code out?

#5

yeah, that’s what I am doing now :slightly_smiling_face: , Thanks a lot for help