Graphics Reference
In-Depth Information
It's also possible to swap the axes so that the names go along the x-axis and the values go along
the y-axis, as shown in
Figure 3-29
. We'll also rotate the text labels by 60 degrees:
ggplot(tophit, aes(x
=
reorder(name, avg), y
=
avg))
+
geom_point(size
=
3
)
+
# Use a larger dot
theme_bw()
+
theme(axis.text.x
=
element_text(angle
=
60
, hjust
=
1
),
panel.grid.major.y
=
element_blank(),
panel.grid.minor.y
=
element_blank(),
panel.grid.major.x
=
element_line(colour
=
"grey60"
, linetype
=
"dashed"
))
Figure 3-29. Dot plot with names on x-axis and values on y-axis
It's also sometimes desirable to group the items by another variable. In this case we'll use the
factor
lg
, which has the levels
NL
and
AL
, representing the National League and the American
League. This time we want to sort first by
lg
and then by
avg
. Unfortunately, the
reorder()
function will only order factor levels by one other variable; to order the factor levels by two vari-
ables, we must do it manually:
# Get the names, sorted first by lg, then by avg
nameorder
<-
tophit$name[order(tophit$lg, tophit$avg)]
# Turn name into a factor, with levels in the order of nameorder
tophit$name
<-
factor(tophit$name, levels
=
nameorder)
