r: ggplot2 条形图显示 Y 轴刻度乱序

Question

I am plotting a multiple grouping bar chart and finding that, although the data is displaying correctly, the chart is completely skewed in it's display because the y-axis tick values are not in numerical order.

Current graph output:

Below is my code, can anyone show me how I can order the values numerically?

     library(ggplot2)
veg_db <- read.csv("filepath\\filename.csv", header = TRUE)
veg_df <- data.frame(veg_db)

veg <- veg_df[c(125),c(4,5,9,12,13,18)]
white_veg <- data.frame(t(veg))
colnames(white_veg) <- c("value")
rownames(white_veg) <- c("Broccoli", "Carrots", "Leafy Greens", "Peas", "Peppers", "Tomatoes")
white_veg <- cbind(vegetables = rownames(white_veg),ethnicity = "white", white_veg)


veg <- veg_df[c(129),c(4,5,9,12,13,18)]
black_veg <- data.frame(t(veg))
colnames(black_veg) <- c("value")
rownames(black_veg) <- c("Broccoli", "Carrots", "Leafy Greens", "Peas", "Peppers", "Tomatoes")
black_veg <- cbind(vegetables = rownames(black_veg),ethnicity = "black", black_veg)

total_veg <- merge(white_veg, black_veg, all = TRUE)
total_veg

plot <- ggplot(total_veg, aes(vegetables, value, fill = ethnicity))+
  geom_bar(position="dodge",stat="identity")


plot

Here is the output of my total_veg dataframe:

total_veg

     vegetables ethnicity value
1      Broccoli     white 10.18
2      Broccoli     black  6.46
3       Carrots     white 12.58
4       Carrots     black  8.54
5  Leafy Greens     white  2.88
6  Leafy Greens     black  1.68
7          Peas     white 19.96
8          Peas     black 13.13
9       Peppers     white  3.09
10      Peppers     black  3.12
11     Tomatoes     white 80.13
12     Tomatoes     black 62.08

Answer 1

Value was a factor rather than numeric (discovered this via str() function).

I used as.numeric(as.character()) to convert value from factor to numeric, which then displayed the data in a meaningful order when plotted. Thanks to @MrFlick for pointing me in the right direction.

Answer 2

I encountered the same issue.

The file that you uploaded might have had that column as a string some value(mine was currency and it had $ in the beginning). Hence it was disordered.

Either re-upload the data in the right format or change it to a numeric value and you would get it plotted right.