changing the position of x-axis labels in bar plots (using base graphics)-CodePudding

I want the black numbers (x-axis labels) to be attached closely below each corresponding bar. red numbers show the results I desire.

the labels I will use are long names that are longer than these numbers but I replaced them with numbers for simplicity's sake.

the change values (changes) I want to plot are 
-2.9900 -2.7300 -2.3100 -1.8000 -1.6800 -1.2700 -1.0500 -1.0400 -0.9200 -0.6600 -0.6400 -0.5900 -0.5000 -0.4900 -0.4200 -0.3800 -0.0500 -0.0300 -0.0200 -0.0100 -0.0100 -0.0100 -0.0100 -0.0100 -0.0100 -0.0100 -0.0100 -0.0040 -0.0040 -0.0005  0.0030  0.4300  0.4500  0.5500  0.6100  0.6200  0.6200   0.6400  2.7200  5.6900
numbers<- 1:40

#barplot
rt<-barplot(change,  main = "change in metabolites after Ramadan ", 
            col = c('grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey'),
        names = numbers,
        ylab = "percentage of Change (%)", 
        ylim = c(-4, 6))

Thank you in advance

Best,

CodePudding user response：

One option is to add an offset to each label position depending on whether it is below or above zero, e.g.

change <- c(-2.9900, -2.7300, -2.3100, -1.8000, -1.6800, 
            -1.2700, -1.0500, -1.0400, -0.9200, -0.6600, 
            -0.6400, -0.5900, -0.5000, -0.4900, -0.4200, 
            -0.3800, -0.0500, -0.0300, -0.0200, -0.0100, 
            -0.0100, -0.0100, -0.0100, -0.0100, -0.0100, 
            -0.0100, -0.0100, -0.0040, -0.0040, -0.0005,  
            0.0030,  0.4300,  0.4500,  0.5500,  0.6100,  
            0.6200,  0.6200,   0.6400,  2.7200,  5.6900)
numbers<- 1:40
rt<-barplot(change,  main = "change in metabolites after Ramadan ", 
            col = c('grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey','grey'),
            names = numbers,
            ylab = "percentage of Change (%)", 
            ylim = c(-4, 6.5))
text(x = rt, y = ifelse(change <= 0, change - 0.25, change   0.25),
     labels = numbers, cex = 0.6, srt = -90, col = "red")

^{Created on 2021-12-20 by the}