Aim:
Say I have a dataframe as follows:
df<-data.frame(A=sample(1:5,20,replace=T),
B=sample(1:5,20,replace=T),
C=sample(1:5,20,replace=T),
D=sample(1:5,20,replace=T))
# A B C D
#1 1 5 4 1
#2 5 4 2 4
#3 3 1 2 1
#4 1 4 5 1
#5 5 3 3 4
#6 3 3 3 1
#7 1 1 2 1
#8 3 2 5 1
#9 5 3 4 3
#10 3 5 5 5
#11 3 4 1 4
#12 2 4 3 5
#13 5 5 5 2
#14 5 1 4 1
#15 2 3 1 4
#16 3 1 5 5
#17 2 3 5 1
#18 2 1 3 3
#19 5 3 1 4
#20 1 2 5 3
Now, I would like to plot a bar chart with the X-axis containing the categorical values 1,2,3,4,5 and the Y-axis as the frequency of the values for each of the columns A to D. Something like this:
Better to mention, I want a single grouped barplot containing this.
What I tried:
I tried to create a table by applying the table command to each of the columns dataframe which gives me a list of tables.
freq<-sapply(df,table)
freq
#$A
#1 2 3 5
#4 4 6 6
#$B
#1 2 3 4 5
#5 2 6 4 3
#$C
#1 2 3 4 5
#3 3 4 3 7
#$D
#1 2 3 4 5
#8 1 3 5 3
This gives me the required values for the table alright, but it provides that in a list.
Where am I stuck:
Well, I tried plotting the barplot by applying the barplot function to each list elements:
par(mfrow=c(2,2))
sapply(freq,barplot)
#$A
# [,1]
#[1,] 0.7
#[2,] 1.9
#[3,] 3.1
#[4,] 4.3
#$B
# [,1]
#[1,] 0.7
#[2,] 1.9
#[3,] 3.1
#[4,] 4.3
#[5,] 5.5
#$C
# [,1]
#[1,] 0.7
#[2,] 1.9
#[3,] 3.1
#[4,] 4.3
#[5,] 5.5
#$D
# [,1]
#[1,] 0.7
#[2,] 1.9
#[3,] 3.1
#[4,] 4.3
#[5,] 5.5
Just as I had expected and as can be guessed from the picture above, I came across two problems in this group of graphs:
- I cannot edit the attributes of the barplot (like colours of plots, main heading, etc.)
- There are 4 individual plots instead of just 1 grouped barplot as I wanted at the beginning
The workaround for the first problem, as I found out after thinking a bit, is to just create a user-defined function and then passing that into sapply (but I cannot give the heading for my plots here, might have to think about that for a bit). A for-loop might be a better option here instead of sapply:
par(mfrow=c(2,2))
for(i in 1:length(freq))
{
barplot(freq[[i]],main=names(freq)[i],col='Red')
}
The problem:
However, I want only one grouped bar plot from this dataset, as I had mentioned in the beginning. But, it seems to me, that I cannot do it. I looked it up online, but couldn't get any satisfactory workarounds. A bit of help regarding this matter would be very much appreciated. Also, a hint, which involves only base R methods is preferred.
