Quick plotting of correlations with P-values

plotAnnotatedScatter.R

# See examples at http://sambuckberry.github.io/2015/07/15/quickCorPlots/

plotAnnotatedScatter <- function(x, y, pointCol=rgb(0,0,0,0.7), 
                                 legendPos="topleft", legendCex=1, ... ){
        # Generate a linear model summary
        fit <- lm(y ~ x)
        fitSum <- summary(fit)
        r2 <- fitSum$r.squared
        pVal <- fitSum$coefficients[2,4]
        
        # Format the legend for r and p values
        rp <- vector('expression',2)
        rp[1] <- substitute(expression(italic(R)^2 == valueA), 
                            list(valueA = format(r2,dig=3)))[2]
        rp[2] <- substitute(expression(italic(p) == valueB), 
                            list(valueB = format(pVal, digits = 2)))[2]
        
        # Plot the data
        plot(x, y, pch=19, cex=1.2, col=pointCol,...)
        
        # Add line for linear model fit
        abline(fit)
        
        # Add the legend
        legend(legendPos, legend = rp, bty = 'n', cex=legendCex)
}