title: Show all date values on ggplot x axis - R
body: <p>In the following little dataset, I would like to plot date values on the x axis. I want all ticks of the dates present in the dataframe to be labelled. At the moment it is only labelling 3 random ticks. I could change the column to a factor, but having as a date means the x axis is spaced according to the time interval between points. So far the only answers I can find are for questions that want to show every month, or at least equally spaced time intervals. I just want to show the values in my dataset. Thank you</p>
  
  <p><strong>Data:</strong></p>
  
  <pre><code>dput(melt)
  structure(list(Sample = structure(c(16023, 16023, 16027, 16027, 
  16031, 16031, 16035, 16035, 16038, 16038, 16044, 16044, 16023, 
  16023, 16027, 16027, 16031, 16031, 16035, 16035, 16038, 16038, 
  16044, 16044), class = "Date"), Treatment = structure(c(1L, 2L, 
  1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
  1L, 2L, 1L, 2L, 1L, 2L), .Label = c("T1", "T5"), class = "factor"), 
      variable = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
      1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L
      ), .Label = c("20:5n-3", "20:4n-6"), class = "factor"), value = c(1.21879849498785, 
      1.88548990818282, 1.87990774775065, 1.25350826053539, 3.10352691206175, 
      1.18465888918519, 3.15176346709818, 1.82106970985234, 2.73680349074891, 
      1.58066166099405, 1.43967823968644, 1.51515884762159, 9.25194151767438, 
      9.23279864348857, 14.0535236345336, 9.06572816754405, 9.90634511302451, 
      10.0962470101343, 7.44314990623579, 12.7996706096935, 5.96573623304832, 
      8.070195431115, 2.57433899670204, 11.4388591839374)), row.names = c(NA, 
  -24L), class = "data.frame")
  </code></pre>
  
  <p><strong>Code:</strong></p>
  
  <pre><code>library(ggplot2)
  
  ggplot(melt, aes(x=Sample, y=value, colour=variable, group=variable))+
    facet_wrap(~Treatment)+
    geom_point()+
    geom_line()
  </code></pre>
  
  <p><strong>Plot:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/JKTEM.png" rel="noreferrer"><img src="https://i.stack.imgur.com/JKTEM.png" alt="enter image description here"></a></p>