# Correlation matrix and plots

## Problem

You want to calculate and visualize the correlation between continuous variables in a dataset.

## Solution

Use functions within the corrplot package, as illustrated with the following example code.

#load required package require(corrplot) #read built-in example data dat <- iris #create pearson correlation matrix of continuous variables (1-4 for this example) M<-cor(dat[,1:4], use="complete.obs", method="pearson") #demo different options to plot/visualize the correlation matrix corrplot(M, method="number") #display pearson correlation

corrplot(M, type="upper", method="number") #only show upper half (removing redundant info)

corrplot(M, method="circle") #display graduated symbols

corrplot.mixed(M, lower="circle", upper="number") #hybrid of both

## Notes

Anne-Marie Hodge and Jason Carlisle contributed to the development of this tool.