We are going to do the Transform step of an Extract-Transform-Load.
Extract-Transform-Load (ETL) is a fancy way of saying, "We have some crufty, legacy data over in this system, and now we need it in this shiny new system over here, so we're going to migrate this."
(Typically, this is followed by, "We're only going to need to run this once." That's then typically followed by much forehead slapping and moaning about how stupid we could possibly be.)
We're going to extract some scrabble scores from a legacy system.
The old system stored a list of letters per score:
- 1 point: "A", "E", "I", "O", "U", "L", "N", "R", "S", "T",
- 2 points: "D", "G",
- 3 points: "B", "C", "M", "P",
- 4 points: "F", "H", "V", "W", "Y",
- 5 points: "K",
- 8 points: "J", "X",
- 10 points: "Q", "Z",
The shiny new scrabble system instead stores the score per letter, which makes it much faster and easier to calculate the score for a word. It also stores the letters in lower-case regardless of the case of the input letters:
- "a" is worth 1 point.
- "b" is worth 3 points.
- "c" is worth 3 points.
- "d" is worth 2 points.
- Etc.
Your mission, should you choose to accept it, is to transform the legacy data format to the shiny new format.
A final note about scoring, Scrabble is played around the world in a variety of languages, each with its own unique scoring table. For example, an "E" is scored at 2 in the Māori-language version of the game while being scored at 4 in the Hawaiian-language version.
Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include a message.
To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
raise Exception, you should write:
raise Exception("Meaningful message indicating the source of the error")To run the tests, run pytest etl_test.py
Alternatively, you can tell Python to run the pytest module:
python -m pytest etl_test.py
-v: enable verbose output-x: stop running tests on first failure--ff: run failures from previous test before running other test cases
For other options, see python -m pytest -h
Note that, when trying to submit an exercise, make sure the solution is in the $EXERCISM_WORKSPACE/python/etl directory.
You can find your Exercism workspace by running exercism debug and looking for the line that starts with Workspace.
For more detailed information about running tests, code style and linting, please see Running the Tests.
The Jumpstart Lab team http://jumpstartlab.com
It's possible to submit an incomplete solution so you can see how others have completed the exercise.