To create a bar chart or histogram using ggplot is easy. Bar charts (or bar graphs) are used to visualise a single categorical variable. Histograms are used to visualise a single numeric variable. Ggplot2 is a powerful package used for data visualisation in R programming. So if you're into data science, statistics or any other quantitative analysis and you're learning to use R, then I recommend that you learn ggplot. This is part of the series: R programming for beginners. ggplot is sometimes referred to as ggplot2