title: Remove space between bars ggplot2
body: <p>This is my code</p>
  
  <pre><code>    ggplot(df, aes(x=timepoint, y=mean, fill=group)) +
              geom_bar(position=position_dodge(.3), colour="black", stat="identity", width=0.3, , binwidth=0) +
              geom_errorbar(position=position_dodge(.3), width=.25, aes(ymin=mean, ymax=mean+sem)) +
              scale_fill_manual(values=c("#FFFFFF", "#000000"), guide=FALSE) +
              theme_bw() +
              ylab(ylab) +
              xlab("") +
              # xlim("Baseline", "12w") +
              scale_x_discrete(expand = c(0,0), limits=c("Baseline","12w")) + 
              scale_y_continuous(expand = c(0,0) ) + 
              theme(panel.border = element_blank(), panel.grid.major = element_blank(), 
                    panel.grid.minor = element_blank(), axis.line = element_line(colour = "black"))
  </code></pre>
  
  <p>This is MY output, which I DONT want, its too much space between "baseline" and "12w":</p>
  
  <p><img src="https://i.imgur.com/IxLhCXS.jpg" alt="enter image description here"></p>
  
  <p>How to remove the space between the bars?</p>
  
  <p>Thank you</p>
  
  <p>df is like this:</p>
  
  <pre><code>df &lt;- structure(list(group = c("a1.d.ffa.mean Dysglyc", "a1.c.ffa.mean Control", 
  "b1.d.ffa.mean Dysglyc", "b1.c.ffa.mean Control"), timepoint = c("Baseline", 
  "Baseline", "12w", "12w"), mean = c(1.913509, 2.181959, 2.742249, 
  1.50846), sem = c(0.10663114, 0.08360294, 0.07890374, 0.08348542
  ), p.value = c(0.597738161, 1, 0.007885464, 1), p.value.t = c(0.04408, 
  1, 0.2455049, 1)), .Names = c("group", "timepoint", "mean", "sem", 
  "p.value", "p.value.t"), class = "data.frame", row.names = c(NA, 
  -4L))
  
  df
  
                    group timepoint     mean        sem     p.value p.value.t
  1 a1.d.ffa.mean Dysglyc  Baseline 1.913509 0.10663114 0.597738161 0.0440800
  2 a1.c.ffa.mean Control  Baseline 2.181959 0.08360294 1.000000000 1.0000000
  3 b1.d.ffa.mean Dysglyc       12w 2.742249 0.07890374 0.007885464 0.2455049
  4 b1.c.ffa.mean Control       12w 1.508460 0.08348542 1.000000000 1.0000000
  </code></pre>