Ploting barplot differently in R - r

Question

Suppose I have the following data frame:
> example
col1 col2 col3
1 -1 1 -1
2 0 -1 3
3 1 10 -1
and I want to plot a barplot and using row 3 as an example, I do barplot(example[3,]). This works perfectly. However, I want to flip the value and add more color -- specifically, I want:
if the value is negative (i.e., -1 in row 3), I want to flip it into +1 and color red when plotting the boxplot. (but note that there are +1 value in the row already and we don't want to color that in red)
if the value is >= +10, color the column green in the boxplot
How can I do the above?
> dput(example)
structure(list(col1 = c(-1, 0, 1), col2 = c(1, -1, 10), col3 = c(-1,
3, -1)), row.names = c(NA, 3L), class = "data.frame")

Answer 1

Here it is a complet solution using only base R :
df <- structure(list(col1 = c(-1, 0, 1),
col2 = c(1, -1, 10),
col3 = c(-1, 3, -1)),
row.names = c(NA, 3L),
class = "data.frame")
# apply conditions on the matrix to color your plot
# If I well understand your demand, it is to have specific color with
# respect to specific condition. Multiply by 2 is to have different factor
level
color <- (df >= 10) * 2 + (df < 0) + 1
# to swap -1 to +1 do that :
df[df < 0] <- df[df < 0] + 2
# set color as wishes
color <- matrix(c("black", "red", "green")[color], nrow = nrow(color), ncol = ncol(color), byrow = F)
# plot the vector we want
barplot(df[,3], col = color[,3])
EDIT 1
To plot the row 3 you can use this trick with transposition function t() :
barplot(t(df)[, 3], col = t(color)[, 3])