ggplots-in-for-loops-dont-work.R

library(ggplot2)

all_plots <- list()

m <- as.matrix(penguins[,3:6])

for (i in 1:ncol(m)) {
  gg <- ggplot(penguins, aes(bill_len, m[,i])) + 
    geom_point() +
    labs(title = sprintf("Column %i", i))
  all_plots[[i]] <- gg
}

gg_for <- patchwork::wrap_plots(all_plots)

manual_plots <- list()

manual_plots[[1]] <- ggplot(penguins, aes(bill_len, m[,1])) + 
    geom_point() +
    labs(title = "Column 1")

manual_plots[[2]] <- ggplot(penguins, aes(bill_len, m[,2])) + 
    geom_point() +
    labs(title = "Column 2")

manual_plots[[3]] <- ggplot(penguins, aes(bill_len, m[,3])) + 
    geom_point() +
    labs(title = "Column 3")

manual_plots[[4]] <- ggplot(penguins, aes(bill_len, m[,4])) + 
    geom_point() +
    labs(title = "Column 4")


gg_manual <- patchwork::wrap_plots(manual_plots)

gg_for | gg_manual

bang bang

for (i in 1:ncol(m)) {
    gg <- ggplot(penguins, aes(bill_len, m[,!!i])) + geom_point() + labs(title = sprintf("Column %i", i))
    all_plots[[i]] <- gg
}

bang bang? nse banned 5ever now.

bang bang operator !!. That's what I've always called it but not sure why

What if...

library(ggplot2)

all_plots <- list()

m <- as.matrix(penguins[,3:6])
m_cols <- colnames(penguins[,3:6])

for (i in 1:ncol(m)) {  
  gg <- ggplot(m, aes(bill_len, .data[[m_cols[i]]])) + 
    geom_point() +
    labs(title = sprintf("Column %i", i))
  all_plots[[i]] <- gg
}

gg_for <- patchwork::wrap_plots(all_plots)
gg_for

I guess it would be wonderful to be able have .data[[i]] instead.