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daily 04/12/2016

    • When you hit the ‘Submit Answer’ button, every line of code is interpreted and executed by R and you get a message whether or not your code was correct. The output of your R code is shown in the console in the lower right corner.
    • You can also execute R commands straight in the console. This is a good way to experiment with R code, as your submission is not checked for correctness.
      • Your time is important, so Romain Francois has written the key pieces in Rcpp to provide blazing fast performance. Performance will only get better over time, especially once we figure out the best way to make the most of multiple processors.
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      • Tabular data is tabular data regardless of where it lives, so you should use the same functions to work with it. With dplyr, anything you can do to a local data frame you can also do to a remote database table. PostgreSQL, MySQL, SQLite and Google bigquery support is built-in; adding a new backend is a matter of implementing a handful of S3 methods.
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      • The bottleneck in most data analyses is the time it takes for you to figure out what to do with your data, and dplyr makes this easier by having individual functions that correspond to the most common operations (group_by, summarise, mutate, filter, select and arrange). Each function does one only thing, but does it well.
    • dplyr provides another innovation over plyr: the ability to chain operations together from left to right with the %.% operator. This makes dplyr behave a little like a grammar of data manipulation:
  • tags: baseball

    • At a relaxed pace, it should take about three weeks to complete the course. The course is for beginners in SQL, R, and dplyr. You also do not have to understand very much about baseball. We will be using the Lahman Baseball Database, R, dplyr, and Microsoft Access. I will show you how to install everything.
    • To create a logical connection between different data sources, you create a relationship

Posted from Diigo. The rest of my favorite links are here.

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Categories: Uncategorized
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