Plotting multiple diagrams on different scales in ggplot2

Question

I want to plot some diagrams beside each other (eg in columns) and write them to one png file. In graphics::plot it works with layout(...) , but how do I arrange diagrams in ggplot2 ?

Is there something I can do with facets?

Example:

require(cars)
require(data.table)
require(tidyr)

df <- as.data.table(mtcars)
df$obs <- seq_len(df[,.N])

df <- as.data.table(pivot_longer(data = df, names_to = "name", values_to = "val", cols = names(df[, !"obs"])))
df[, name := as.factor(name)]

library(ggplot2)
g <- ggplot(data = df)
g <- g + aes(x = df[, obs], y = df[, val])
g + facet_wrap(df[, name]) + geom_line()

It is not perfect. This gives me a matrix of diagrams for all properties of mtcars . But the y axis is always set to the maximum of the largest value of all properties.

I want the y axis to have the optimum range for each property.

Another thing is, how to plot different tables in the same file:

df1 <- as.data.table(mtcars)[, 1]
df1$obs <- seq_len(df1[,.N])
df2 <- as.data.table(mtcars)[, 2]
df2$obs <- seq_len(df2[,.N])

g1 <- ggplot(data = df1)
g1 <- g1 + aes(x = df1[, obs], y = df1[, mpg])
g1 + geom_line()

g2 <- ggplot(data = df2)
g2 <- g2 + aes(x = df2[, obs], y = df2[, cyl])
g2 + geom_line()

How can I arrange my plots? I don't want them to be plotted in the same diagram. They should have their own axes and titles.

Answer 1

Just free your scale using scales="free" option.

g + facet_wrap(df[, name], scales="free") + geom_line()

For your second question, you may want to consult this answer: Side-by-side plots with ggplot2