"Error: Mapping Should Be Created with `Aes()` or `Aes_()`."

I had the same error, even if I was using aes(). So I used mapping argument before aes().

ggplot() +
geom_boxplot(df, mapping = aes(x = sp, y = cov))

Two mistakes:

1. Brackets have to be closed after ggplot and calling histogram comes after
2. you specify your data set when you call ggplot on df. Therefore there is no need to add df$sp. sp is enough.

This code should work (if there is nothing wrong with your data):

    ggplot(df, aes(sp, cov)) + geom_histogram()

Do not use $ in aes. Only specify the dataset in ggplot. I used plot<-df %>% ggplot()

Yes, it works . You should not use the dollar sign $ if you have specified the data already. I had the same problem and when I removed the dollar sign, it worked.

ggplot(dat1, aes(Q84, REGION, fill = Q3)) +
  geom_bar(stat = "Identity") +
  facet_grid(REGION ~ Q84)

Avoid this:

ggplot(dat1, aes(dat1$Q84, dat1$REGION, fill = Q3)) +
  geom_bar(stat = "Identity") +
  facet_grid(dat1$REGION ~ Q84)

where dat1 is the name of my dataset.

try

ggplot(df, aes(df$sp, df$cov))+ geom_histogram()

instead of

ggplot(df, aes(df$sp, df$cov) + geom_histogram())

displacement of brackets

As another potential solution, I found that having library(cowplot) and library(ggplot2) loaded at the same time made "ggsave("test.pdf", p1)" not work.

Instead, use the cowplot syntax "save_plot("test.pdf", p1)"

The main error is that you closed the bracket at the wrong place this is because we added geom.histogram as new function not an argument of ggplot. Instead, try below code

ggplot(df, aes(df$sp, df$cov)) + geom_histogram()