batronic

stephan.com 2014

In fullfilment of a coding test

Overview

For this scenario, we have been asked to write an application that will be used to provide information about baseball player statistics.

Usage

Uses sqlite, so there's no need to db:create. Use DATABASE_ENV instead of RAILS_ENV

Expects Ruby 2

• git clone https://github.com/stephancom/batronic
• cd batronic
• bundle install
• rake db:migrate
• rake db:migrate DATABASE_ENV=test
• rspec
• rake seeds:all
• ruby batronic.rb

Assumptions

All requests currently are based on data in the hitting file. Future requests of the system will require data from a pitching file as well. Consider this in the design.

note I am assuming that all computed values should be limited to three significant digits after the decimal point, per baseball convention.

Requirements

When the application is run, use the provided data and calculate the following results and write them to STDOUT.

1. Most improved batting average( hits / at-bats) from 2009 to 2010. Only include players with at least 200 at-bats.
2. Slugging percentage for all players on the Oakland A's (teamID = OAK) in 2007.
3. Who was the AL and NL triple crown winner for 2011 and 2012. If no one won the crown, output "(No winner)"

Formulae:

Batting average = hits / at-bats

Slugging percentage = ((Hits – doubles – triples – home runs) + (2 * doubles) + (3 * triples) + (4 * home runs)) / at-bats

Triple crown winner – The player that had the highest batting average AND the most home runs AND the most RBI in their league. It's unusual for someone to win this, but there was a winner in 2012. “Officially” the batting title (highest league batting average) is based on a minimum of 502 plate appearances. The provided dataset does not include plate appearances. It also does not include walks so plate appearances cannot be calculated. Instead, use a constraint of a minimum of 400 at-bats to determine those eligible for the league batting title.

Data

All the necessary data is available in the two csv files attached:

• Batting-07-12.csv

  Contains all the batting statistics from 2007-2012.

  Column header key

  • AB – at-bats
  • H – hits
  • 2B – doubles
  • 3B – triples
  • HR – home runs
  • RBI – runs batted in

• Master-small.csv

  Contains the demographic data for all baseball players in history through 2012.

References

http://exposinggotchas.blogspot.com/2011/02/activerecord-migrations-without-rails.html http://blog.flatironschool.com/post/58164473975/connecting-ruby-active-record-without-rails