Sometimes you will need to add some points to an existing barplot. You might try

par(mfrow = c(1,2))
df <- data.frame(stolpec1 = 10 * runif(10), stolpec2 = 30 * runif(10))
barplot(df$stolpec1)
lines(df$stolpec2/10) #implicitno x = 1:10
points(df$stolpec2/10)

but you will get a funky looking line/points. It’s a bit squeezed. This happens because bars are not drawn at intervals 1:10, but rather on something else. This “else” can be seen if you save your barplot object. You will notice that it’s a matrix object with one column – these are values that are assumed on x axis. Now you need to feed this to your lines/points function as a value to x argument and you’re all set.

df.bar <- barplot(df$stolpec1)
lines(x = df.bar, y = df$stolpec2/10)
points(x = df.bar, y = df$stolpec2/10)

Another way of plotting this is using plotrix package. The controls are a bit different and it takes some time getting used to it.

library(plotrix)
barp(df$stolpec1, col = "grey70")
lines(df$stolpec2/10)
points(df$stolpec2/10)

*Related*

To

**leave a comment** for the author, please follow the link and comment on his blog:

** Dang, another error**.

R-bloggers.com offers

**daily e-mail updates** about

R news and

tutorials on topics such as: visualization (

ggplot2,

Boxplots,

maps,

animation), programming (

RStudio,

Sweave,

LaTeX,

SQL,

Eclipse,

git,

hadoop,

Web Scraping) statistics (

regression,

PCA,

time series,

trading) and more...

If you got this far, why not

__subscribe for updates__ from the site? Choose your flavor:

e-mail,

twitter,

RSS, or

facebook...