How to rearrange the rows of a matrix in R - r

Question

I have the following data frame:
> agg_2
# A tibble: 3 × 3
bcs default_flag pred_default
<chr> <dbl> <dbl>
1 high-score 0.00907 0.0121
2 low-score 0.0345 0.0353
3 mid-score 0.0210 0.0204
I plot it as a bar plot using the following code:
barplot(t(as.matrix(agg_2[,-1])),
main = "Actual Default vs Predicted Default",
xlab = "Score Category",
ylab = "Default Rate",
names.arg = c("High Score", "Low Score", "Mid Score"),
col = gray.colors(2),
beside = TRUE)
legend("topleft",
c("Default", "Pred. Default"),
fill = gray.colors(2))
and it gives me this:
How can I rearrange the data frame/matrix so that the pairs of bars in the bar plot are as follows: Low Score then Mid Score then High Score?

Answer 1

Here is one potential solution:
agg_2 <- read.table(text = "bcs default_flag pred_default
high-score 0.00907 0.0121
low-score 0.0345 0.0353
mid-score 0.0210 0.0204", header = TRUE)
agg_2$bcs <- factor(agg_2$bcs, levels = c("low-score", "mid-score", "high-score"), ordered = TRUE)
agg_2 <- agg_2[order(agg_2$bcs),]
barplot(t(as.matrix(agg_2[,-1])),
main = "Actual Default vs Predicted Default",
xlab = "Score Category",
ylab = "Default Rate",
names.arg = agg_2$bcs,
col = gray.colors(2),
beside = TRUE)
legend("topright",
c("Default", "Pred. Default"),
fill = gray.colors(2))
Created on 2022-06-21 by the reprex package (v2.0.1)