在R中收集多个列，然后创建Boxplot

Question

I´m pretty new to R, and got stuck trying to make a boxplot. I have a dataset with 18 variables and almost 20 000 rows. Looks something like this like this:

1 EnsemblID GeneName   Sample1A   Sample1B   Sample2A   Sample2B       
2 ENSG00000180096   ABCD   0.000000   0.378398   0.256493   0.488798   
3 ENSG00000247626   ACED  20.770695  17.456049  19.066029  17.960966  

I want to make a boxplot per gene (column GeneName), with the values from sample 1 in one box (1A, 1B) and sample 2 in a different box (2A, 2B). In reality I have three groups with 5-6 replicates each. How do I melt into a tall dataframe like this?

1 GeneName Group Value  
2 ABCD Sample1A 0.000000  
3 ABCD Sample1B 0.378398  
4 ABCD Sample2A 0.256493  
5 ABCD Sample2B 0.488798    
6 ACED Sample1A 20.770695   
7 ACED Sample1B 17.456049    
8 ACED Sample2A 19.066029  
9 ACED Sample2B 17.960966

And how can I make a boxplot to show the variation for each gene within and between each group?

Would appreciate any help! Thanks!

Answer 1

using tidyr from the tidyverse

df <- read.table(header = T, text ="
1 EnsemblID GeneName Sample1A Sample1B Sample2A Sample2B
2 ENSG00000180096 ABCD 0.000000 0.378398 0.256493 0.488798
3 ENSG00000247626 ACED 20.770695 17.456049 19.066029 17.960966
")

library(tidyr)

df <- gather(df, Group, Value, Sample1A:Sample2B)
boxplot(Value ~ Group, df)