title: connecting points with lines in ggplot2 in r
body: <p>Here is my data:</p>
  
  <pre><code>    mydata &lt;- data.frame (grp = c(  1,   1,   1,  1, 1,  1, 1, 1, 1, 
       2,2, 2, 2,2, 2, 2, 2, 2),
      grp1 = c("A", "A", "A", "A", "A",  "B", "B", "B", "B" ,  
      "A", "A", "A", "A",      "B", "B", "B", "B", "B"), 
     namef = c("M1", "M3", "M2", "M4", "M5","M1", "M3", "M4", 
      "M0", "M6", "M7", "M8",       "M10", "M6", "M7", "M8", "M9", "M10"),
       dgp = c(1, 1, 1, 1, 1,  1.15, 1.15,1.15, 1.15 ,
          2, 2, 2, 2,2.15, 2.15, 2.15, 2.15, 2.15), 
      position = c(1.1, 2.1, 3.2, 4.1, 5.0,
       1.1, 2.0, 5.0, 6.2, 1.0,3.0, 4.1, 5.0,  
      1.0, 2.1, 3.01, 4.0, 5.02))
  
  require(ggplot2)
  
  plt &lt;- ggplot(mydata) +   geom_point(aes(position, dgp, 
  group = factor(dgp)),   size = 2, colour = "purple") +
  geom_text(data = mydata,aes(x=position,y=dgp + 0.05,
   label=namef))
  </code></pre>
  
  <p>plt</p>
  
  <p>I want to connect point with same label from variable namef.
  <img src="https://i.stack.imgur.com/ohxgW.png" alt="enter image description here"></p>
  
  <p>I thought geom_segment is appropriate to handle the situation:</p>
  
  <pre><code>require(grid)
  plt + geom_segment(aes(xend = position, yend = dgp), 
  arrow = arrow(length = unit(0.1,"cm")))
  </code></pre>