title: "missing value where TRUE/FALSE needed" error vcd::mosaic
body: <pre><code>&gt; library(vcd)
  Loading required package: MASS
  Loading required package: grid
  Loading required package: colorspace
  &gt; library(MASS)
  &gt; tbl = table(survey$W.Hnd,survey$Fold)
  &gt; print(tbl)
  
          L on R Neither R on L
    Left      10       1      7
    Right     88      17    113
  &gt; mosaic(tbl)
  Error in if (split_vertical[i]) { : missing value where TRUE/FALSE needed
  Calls: mosaic -&gt; mosaic.default -&gt; strucplot -&gt; labeling
  Execution halted
  </code></pre>
  
  <p>Why am I getting this error, and how to fix the code?</p>
  
  <hr>
  
  <p>Easy paste code here:</p>
  
  <pre><code>library(vcd)
  library(MASS)
  tbl = table(survey$W.Hnd,survey$Fold) # survey is a library data set in MASS
  print(tbl)
  mosaic(tbl) # produces the above error
  </code></pre>