ggpol (version 0.0.5)

facet_share: A shared axis for two panels

Description

`facet_share` uses [facet_wrap()] to build two panels with a shared axis.

Usage

facet_share(facets, scales = "fixed", reverse_num = FALSE,
  shrink = TRUE, labeller = "label_value", as.table = TRUE,
  switch = NULL, drop = TRUE, dir = "h", strip.position = "top")

Arguments

facets

A set of variables or expressions quoted by vars() and defining faceting groups on the rows or columns dimension. The variables can be named (the names are passed to labeller).

For compatibility with the classic interface, can also be a formula or character vector. Use either a one sided formula, ~a + b, or a character vector, c("a", "b").

scales

Should scales be fixed ("fixed", the default), free ("free"), or free in one dimension ("free_x", "free_y")?

reverse_num

Used when passing on flipped data (times -1) for the second (right/bottom) panel. If `TRUE`, this will multiply the axis labels for that panel by -1.

shrink

If TRUE, will shrink scales to fit output of statistics, not raw data. If FALSE, will be range of raw data before statistical summary.

labeller

A function that takes one data frame of labels and returns a list or data frame of character vectors. Each input column corresponds to one factor. Thus there will be more than one with formulae of the type ~cyl + am. Each output column gets displayed as one separate line in the strip label. This function should inherit from the "labeller" S3 class for compatibility with labeller(). See label_value() for more details and pointers to other options.

as.table

If TRUE, the default, the facets are laid out like a table with highest values at the bottom-right. If FALSE, the facets are laid out like a plot with the highest value at the top-right.

switch

By default, the labels are displayed on the top and right of the plot. If "x", the top labels will be displayed to the bottom. If "y", the right-hand side labels will be displayed to the left. Can also be set to "both".

drop

If TRUE, the default, all factor levels not used in the data will automatically be dropped. If FALSE, all factor levels will be shown, regardless of whether or not they appear in the data.

dir

Direction: either "h" for horizontal, the default, or "v", for vertical.

strip.position

By default, the labels are displayed on the top of the plot. Using strip.position it is possible to place the labels on either of the four sides by setting strip.position = c("top", "bottom", "left", "right")

Examples

# NOT RUN {
df <- data.frame(age = sample(1:20, 1000, replace = TRUE), 
                 gender = c("M","F"), levels = c("M", "F"))

# Get the count per age and sex
df$count <- 1
df <- aggregate(count ~ gender + age, data = df, length)

# For the horizontally shared axis, if we want to mirror the axes,
# we have to multiply the first panel by -1, and use coord_flip().
df_h <- df 
df_h$count = ifelse(df_h$gender == "F", df_h$count * -1, df_h$count)

p <- ggplot(df_h, aes(x = factor(age), y = count, fill = gender)) + 
  geom_bar(stat = "identity") +
  facet_share(~gender, dir = "h", scales = "free", reverse_num = TRUE) + 
  coord_flip() +
  labs(x = "Age", y = "Count") + 
  theme(legend.position = "bottom")

p

# When setting direction to vertical, and if we want to mirror the second panel,
# we must multiply the second factor by -1.
# And levels(factor(gender))[2] is M. 
df_v <- df
df_v$count <- ifelse(df_v$gender == "M", df_v$count * -1, df_v$count) 

p <- ggplot(df_v, aes(x = as.factor(age), y = count, fill = gender)) + 
  geom_bar(stat = "identity") +   
  facet_share(~gender, dir = "v", reverse_num = TRUE, 
              scales = "free", strip.position = "left") +
  labs(x = "Age", y = "Count") + 
  theme(legend.position = "left")
p
# }