continuous variable _x |
discrete variable_x |
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<Three ways to make a Bar graph>
> table(mpg$cyl)
4 5 6 8
81 4 79 70
>barplot(table(mpg$cyl))
> ggplot(data=mpg,aes(x=cyl))+geom_bar()
> qplot(mpg$cyl,binwidth=0.5)
When the variable x is a numeric value, the variable is regarded as continuous variable using ggplot()-geom_bar(),geom_col() and the graph becomes containing the vacant element. (ex) cyl=7 above
You can make the variable discrete by using factor().
<Make a Discrete bar graph with an originally continuous variable>
Instead of having a blank in the bar graphs above, we can delete the case when x=7 by making the variable mpg$cyl be discrete. There are three ways to make a bar graph of a discrete variable from a continuous variable.
> qplot(factor(mpg$cyl))
> ggplot(mpg,aes(x=factor(cyl)))+geom_bar()
> barplot(table(mpg$cyl))
