barplot(): Frequency percentages per group

问题

I'm trying to make a grouped barplot with frequency (%) on the y-axis and depression_meds (N/Y) on the x-axis, grouped by another variable score (LOW/HIGH).

My code so far:

meds <- table(data2$depression_meds,data2$score)/sum(table(data2$score)) * 100
bp <- barplot(meds, beside=TRUE, axes=FALSE, xlab="Anti-depression meds use", names=c("No", "Yes"), col=c("azure3", "azure"), ylab="Frequency (%)", ylim=c(0,100))
axis(2, at=seq(0,100,10))
legend("topright", legend=c("LOW", "HIGH"), bty="n", fill=c("azure3", "azure"))
text(bp, 0, round(medtimerx, 1), cex=1, pos=3)

Which is great and makes the following barplot:

But the percentages are using the total n of 243 (3rd column of the table below), not the n per score group (1st and 2nd columns in table below), which makes sense because that is what I do when I divide by the sum. But that's not what I want. I keep trying to get the frequencies per score group so that the four bars match the 1st and 2nd columns below, but I have run out of ideas. Does anyone have any suggestions?

Depression meds (0=N, 1=Y)   LOW (N=99)   HIGH (N=144)   TOTAL (N=243)
                         0   96 (97.0%)   116 (80.6%)    212 (87.2%)     
                         1   3 (3.0%)     28 (19.4%)     31 (12.8%)

Here is my data:

> dput(data2)
structure(list(depression_meds = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 
1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 1L, 0L, 0L, 0L, 0L, 0L, 1L, 
0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 1L, 0L, 0L, 0L, 
0L, 0L, 0L, 1L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 1L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 
0L, 1L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L), score = c(1L, 
1L, 0L, 0L, 0L, 0L, 1L, 1L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 1L, 1L, 
0L, 0L, 1L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 1L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 1L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 0L, 0L, 0L, 1L, 0L, 1L, 0L, 1L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L)), .Names = c("depression_meds", "score"), row.names = c(NA, 
-243L), class = "data.frame")

Thanks for your help, my brain isn't working any longer.

回答1:

Use this for your summary table:

meds <- table(data2)

#               score
#depression_meds   0   1
#              0  96 124
#              1   3  20

meds <- scale(meds, FALSE, colSums(meds)) * 100

#               score
#depression_meds         0         1
#              0 96.969697 86.111111
#              1  3.030303 13.888889

No need to change your the rest of your code:

bp <- barplot(meds, beside=TRUE, axes=FALSE, xlab="Anti-depression meds use", names=c("No", "Yes"), col=c("azure3", "azure"), ylab="Frequency (%)", ylim=c(0,100))
axis(2, at=seq(0,100,10))
legend("topright", legend=c("LOW", "HIGH"), bty="n", fill=c("azure3", "azure"))
text(bp, 0, round(meds, 1), cex=1, pos=3)

回答2:

Using prop.table in this case is very suitable, which provides a margin parameter to specify by row or by column probability calculation:

meds <- prop.table(table(data2), margin = 2) * 100
meds
#                score
# depression_meds         0         1
#               0 96.969697 86.111111
#               1  3.030303 13.888889

来源：https://stackoverflow.com/questions/38530512/barplot-frequency-percentages-per-group

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