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If you are just starting out in R it’ll be important to know how to determine your working directory or how to find the files you may have saved. Luckily getting, setting or changing your working directory in R is easy and should be part of any cheat sheet you might be keeping handy. >…

Reading a table in R is quite straight-forward. We are going to read a table from the web and also one locally. If you have come across a .dat file and want to import that table into R you’ll find this to be incredibly easy compared to other imports. We will use a Princeton dataset,…

There are a few different ways to import data into R. We will cover two ways in this post, downloading a file from the web and getting a file from your computer. We will walk through downloading and importing that a CSV file from the web and then a similar CSV from our computer. If…

We will walk you through how to run random sampling in R, but first lets discuss what is random sampling and why is it useful? Right now we are in the middle of an election. If you are wondering how pollsters are predicting who will win then you are going to be interested in random…

Lets learn how to generate random numbers in R. There might be occasions where you’d want to draw random numbers but want to be able to replicate those random numbers. To replicate we will set a seed, which means we are locking in the sequence of random numbers that R gave us originally and allows…

What is str? Str is a compact way to display the structure of an R object. This allows you to use str as a diagnostic function and an alternative to summary. Str will output the information on one line for each basic structure. Str is best for displaying contents of lists. The goals is to…

The lapply function in R applies a function to elements in a list or a vector and returns the results in a list. lapply(list, function, …) The lapply function is best for working with data frames. In R the data frame is considered a list and the variables in the data frame are the elements…

Previously we showed you how to write a loop in R. Very often it’s a better idea to use the apply function in R than to write a loop. So what is the apply function in R? Well, apply is really a family of functions that have varying uses. Here are the available R apply…

Just apply! What does that even mean? Well, some R programmers will tell you to use the apply function (lapply or sapply) to loop. Why? because R supports vectors. So, a for loop is slower. I’m not sure this is always true nor does it matter for this how to exercise. However, the next tutorial…