R For Beginners:  Some Simple R Code to Load a Data File and Produce a Histogram

A tutorial by D. M. Wiig

I have found that a good method for learning how to write R code is to examine complete code segments written to perform specific tasks and to modify these procedures to fit your specific needs. Trying to master R code in the abstract by reading a book or manual can be informative but is more often confusing.  Observing what various code segments do by observing the results allows you to learn with hands-on additions and modifications as needed for your purposes.

In this document I have included a short video tutorial that discusses  loading a dataset from the R library, examining the contents of the dataset and selecting one of the variables to examine using a basic histogram.  I have included an annotated code chunk of the procedures discussed in the video.

The video appears below with the code segment following.

Here is the annotated code used in the video:

###################################
#use the dataset mtcars from the ‘datasets’ package
#select the variable mpg to do a histogram
#show a frequency distribution of the scores
##########################################
#library is ‘datasets’
#########################################
library(“datasets”)
#########################################
#take a look at what is in ‘datasets’
#########################################
library(help=”datasets”)
#######################################
#take a look at the ‘mtcars’ data
#########################################
View(mtcars)
#######################################
#now do a basic histogram with the hist function
###########################################
hist(mtcars$mpg)
#############################################
#dress up the graph; not covered in the video but easy to do
############################################
hist(mtcars$mpg, col=”red”, xlab = “Miles per Gallon”, main = “Basic Histogram Using ‘mtcars’ Data”)
###################################################