Legend function in R adds legend box to the plot. legend() function in R makes graph easier to read and interpret in better way. lets see an example on how to add legend to a plot with legend() function in R.
Syntax of Legend function in R:
| x, y | the x and y co-ordinates which is used to position the legend. |
| legend | a character vector of legend names |
| fill | fill legend box with the specified colors. |
| col | the color of points or lines appearing in the legend. |
| border | the border color for the legend box |
| lty, lwd | the line types and widths for lines appearing in the legend. |
| pch | the plotting symbols appearing in the legend |
Example of Legend function in R:
Let’s depict how to create legend in R with an example.
#plot a scatter plot x1 <- c(3,3,4,-3,-2,5,2) y1 <- c(2,4,2,2,-3,3,7) plot(x1,y1,cex=.8,pch=1,xlab="x axis",ylab="y axis",col="red")
output will be
#plot an another scatter plot with points function x2 <- c(1,2,-2,-1,-2,3) y2 <- c(2,3,2,2,-2,3) points(x2,y2,cex=.8,pch=2,col="blue")
So the resultant chart will be
Add legend to the top left corner of the plot with legend function in R:
Now let’s add the legend to the above scatter plot with legend function in R, to make it more readable
## adding legend to the top left of the plot
legend(x=-3,y=7,c("sample1","sample2"),cex=.8,col=c("red","blue"),pch=c(1,2))
In the above function we have added legend to the top left corner of the graph at co-ordinates x= -3 and y=7 so the output will be
Add legend to the top right corner of the plot with legend function in R:
## adding legend to the top right corner of the plot
legend(x=4,y=7,c("sample1","sample2"),cex=.8,col=c("red","blue"),pch=c(1,2))
In the above function we have added legend to the top right corner of the graph at co-ordinates x= 4 and y=7 so the output will be
