Part V of tree based methods in R series. Performance of regression analysis is discussed.

Part IV of tree based methods in R series. 3 R packages for classification analysis are compared - rpart, caret and mlr packages.

Part III of tree based methods in R series. Regression tasks are discussed.

Part II of tree based methods in R series. Cost-sensitive classification is implemented, assuming that misclassifying the High class is twice as expensive, both by altering the priors and by adjusting the loss matrix.

Part I of tree based methods in R series. Classification analysis is performed using the caret package.

This is a quick trial of adding overall and conditional (by user) average columns in a data frame.

We discuss how to loop without for in R.

I demonstrate short R examples - summarise a data frame group by a column and a quick way of implementing simulation

This post is a slight extension of the previous two articles - Download Stock Data - Part I and Download Stock Data - Part II. We discuss how to produce gross returns, standard deviation and correlation of multiple shares.

In an earlier article, a way to download stock price data files from Google, save it into a local drive and merge them into a single data frame. If files are not large, however, it wouldn't be effective and, in this article, files are downloaded and merged internally.