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Quantisan edited this page Aug 24, 2012 · 28 revisions

Cascalog for the Impatient

Welcome to Cascalog for the Impatient, a series of blog posts and Cascalog code examples to get you started. Quickly. Like, yesterday.

Use this tutorial in conjunction with Cascading for the Impatient.

  • Implements simplest Cascalog query possible
  • Copies each TSV line from source to sink
  • Roughly, in about a dozen lines of code
  • Implements a simple example of WordCount
  • Uses a regex to split the input text lines into a Tuple stream of tokens
  • Uses a custom Cascalog operator
  • Uses a built-in Cascalog operator
  • Introduction to logic programming

TO-DO

  • Uses a custom Function to scrub the token stream
  • Discusses when to use standard Operations vs. creating custom ones
  • Shows how to join sources together
  • Filters a list of stop words out of the token stream
  • Uses a Predicate Macro
  • Calculates TF-IDF by breaking the problem into sub-queries
  • Shows using an abstracted, re-useable sub-query as a function
  • Includes unit tests in the build
  • Shows how to use other TDD features: checkpoints, assertions, traps, debug

If you want to read in more detail about the Cascalog API which were used, see the Cascalog Wiki and JavaDoc.

For more discussion, see the cascalog-user email forum.

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