Adjust the text in the center with a bias

Question

Using this code

library(ggplot2) ggplot( dat,aes(x=factor(group),y=difference) ) + geom_bar( width=.75,aes(fill=as.factor(Mutation)),stat="identity", position="dodge") + geom_text(aes(label=Mutation),position=position_dodge(height=0.9),angle=90)+ theme_bw() + theme(legend.position="none") 

I generate a smooth schedule. As you can see, some text is not in the center of the bars. I tried some options like hjust , vjust or playing with dodge width , without success. Can someone help me get the text in the center of the bars?

In the graph below, we have a problem with the group = 1, 3,8,9, ...

Here is my details:

 dat <- structure(list(Mutation = structure(1:21, .Label = c("2rN7y", "2wTys", "8ElEj", "8esgR", "8ppm9", "BkuXt", "bM5sv", "c7KTn", "dnBl6", "F5nhO", "fFpM6", "hMpSW", "HxAh9", "KDI0t", "qZTSa", "rOONr", "Tf2kX", "TGDZE", "tLdje", "XsGz6", "XTGN1"), class = "factor"), difference = c(2.1499193357556, 0.27602347826589, -0.22889581513082, -0.77297822818092, -0.468200478640476, -0.735026155784277, -0.900791750580477, -1.33435362820732, 0.412022274758476, 0.495870479997156, 0.793585307678721, 1.22839278213642, -1.0700682293443, 0.63436212480624, -0.152410633064764, 1.23397624015726, -0.520869343832941, 1.62320252173067, -0.24168976773895, -1.04897550447309, 1.68588724420516 ), position = c(4, 4, 3, 2, 3, 3, 2, 3, 2, 5, 2, 2, 2, 5, 5, 5, 2, 4, 5, 4, 2), group = c(0L, 0L, 1L, 2L, 3L, 3L, 4L, 5L, 6L, 7L, 8L, 8L, 8L, 9L, 9L, 9L, 10L, 11L, 12L, 13L, 14L )), .Names = c("Mutation", "difference", "position", "group" ), row.names = c(11L, 2L, 19L, 10L, 9L, 21L, 20L, 12L, 16L, 13L, 17L, 1L, 6L, 15L, 18L, 14L, 4L, 5L, 8L, 3L, 7L), class = "data.frame") 

Answer 1

I use the @cyclondude idea and generate it with tapply to create a customization vector.

 dat$group_adjust <- unlist(tapply(dat$group,dat$group, function(x) if(length(x)==1) 0 else seq(-length(x)/2,length(x)/2,length=length(x)))) 

The final plot is as follows:

 library(ggplot2) ggplot( dat,aes(x=factor(group),y=difference) ) + geom_bar( width=.75,aes(fill=as.factor(Mutation)),stat="identity", position=position_dodge(height=0.9)) + geom_text(aes(label=Mutation, vjust = group_adjust,y=0),angle=90)+ theme_bw() + theme(legend.position="none") + ylim(extendrange(dat$difference)) 

Answer 2

I still feel like I'm at the beginning of learning to use ggplot2, but maybe you can adapt what I did to a plot that looks closer to what you want. If someone more experienced could direct me to a better coding style for this problem, I would appreciate it.

 n_in_group <- summary(as.factor(dat$group)) group_adjust <- c() for(i in seq(n_in_group)) { if(n_in_group[i] == 1) {group_adjust <- c(group_adjust,0) } if(n_in_group[i] == 2) {group_adjust <- c(group_adjust,-1,1) } if(n_in_group[i] == 3) {group_adjust <- c(group_adjust,-1,0,1)} } library(ggplot2) ggplot( dat,aes(x=factor(group),y=difference) ) + geom_bar( width=.75,aes(fill=as.factor(Mutation)),stat="identity", position="dodge") + geom_text(aes(label=Mutation, vjust = group_adjust),angle=90)+ theme_bw() + theme(legend.position="none")