title: ggplot2, Ordering y axis
body: <p>I have the below data.frame called <code>df</code>. My problem has to do with the order on the y-axis. I want that the names on the y-axis are ordered according to the variable <code>depth</code>.</p>
  
  <p>If I do this:</p>
  
  <pre><code>ggplot(df,aes(x=factor(name),y=depth)) + geom_bar(stat='identity') + coord_flip() + labs(y='depth',x='species')
  </code></pre>
  
  <p>I got <code>graph1</code> below which is not ordered. Therefore I followed the instructions found <a href="https://stackoverflow.com/questions/8713462/ggplot2-change-order-of-display-of-a-factor-variable-on-an-axis">here</a>, I ordered the levels of my factor <code>name</code> according to depth:</p>
  
  <pre><code>df2=df[order(df$depth),]
  df2$name=factor(df2$name,levels=df2$name)
  ggplot(df2,aes(x=factor(name),y=depth)) + geom_bar(stat='identity') + coord_flip() + labs(y='depth',x='species')
  </code></pre>
  
  <p>I got <code>Graph2</code> below. But the next step for me was to color the bars differently depending on the <code>Mut</code> variable.</p>
  
  <pre><code>ggplot(df2,aes(x=factor(name),y=depth)) + geom_bar(stat='identity',data=subset(df2,df2$Mut==2),fill='red') + geom_bar(stat='identity',data=subset(df2,df2$Mut==1),fill='blue') + coord_flip() + labs(y='depth',x='species')
  </code></pre>
  
  <p>And I got <code>Graph3</code> which is not ordered anymore!!</p>
  
  <p><strong>How can I produce graph3 respecting the order displayed in graph2</strong></p>
  
  <pre><code>                    name depth Mut            x
  25  A_rubrocinctus_GA070     8   2 -0.033318659
  9      A_omanensis_GA051    10   2 -0.020387101
  4  A_latifasciatus_GA083    12   1 -0.005645811
  27      A_frenatus_GA068    12   1 -0.024190876
  13       A_percula_GA017    15   1  0.034591721
  14       A_percula_GA039    15   2  0.034591721
  15       A_percula_GA053    15   2  0.034591721
  16     A_ocellaris_GA009    15   1  0.052042539
  17     A_ocellaris_GA021    15   1  0.052042539
  24     A_ephippium_GA057    15   2 -0.016859412
  20   P_biaculeatus_GA008    16   1 -0.014466403
  21   P_biaculeatus_GA025    16   1 -0.014466403
  22   P_biaculeatus_GA065    16   1 -0.014466403
  23     A_melanopus_GA034    18   2 -0.026915545
  26     A_melanopus_GA012    18   2 -0.026915545
  12  A_sandaracinos_GA018    20   1  0.055839755
  6       A_nigripes_GA055    25   1  0.023420045
  8          A_sebae_GA029    25   1  0.021767793
  11   A_akallopisos_GA067    25   1  0.043272525
  28   A_akallopisos_GA072    25   1  0.043272525
  34     A_akindynos_GA032    25   1 -0.020707141
  1       A_polymnus_GA004    30   1  0.030902254
  3        A_allardi_GA033    30   1 -0.020277664
  5      A_bicinctus_GA036    30   1 -0.025354572
  7       A_polymnus_GA019    30   1  0.030902254
  32  A_chrysopterus_GA040    30   1 -0.022402365
  33  A_chrysopterus_GA031    30   1 -0.022402365
  35   A_perideraion_GA020    38   1  0.052830132
  36   A_perideraion_GA015    38   1  0.052830132
  2     A_tricinctus_GA058    40   1 -0.016230301
  18  A_chrysogaster_GA080    40   1  0.012608835
  19  A_chrysogaster_GA077    40   1  0.012608835
  10   A_latezonatus_GA023    45   1 -0.010718845
  31    A_mccullochi_GA056    45   1 -0.031664307
  29       A_clarkii_GA044    60   1 -0.014474658
  30       A_clarkii_GA010    60   1 -0.014474658
  </code></pre>
  
  <p><strong>Graph1</strong>
  <img src="https://i.stack.imgur.com/u4Ia9.png" alt="enter image description here">
  <strong>Graph2</strong>
  <img src="https://i.stack.imgur.com/RJOfw.png" alt="enter image description here">
  <strong>Graph3</strong>
  <img src="https://i.stack.imgur.com/T29Jm.png" alt="enter image description here">
  Thank you!</p>