title: remove singularities, "NAs" from R output
body: <p>I got a piece of R code as below, there are about 256 coefficients by looking at the summary output, basically what I want to do is to remove the NA coefficients (due to singularities?) and leave the R output with 64 coefficients with estimations.</p>
  
  <pre><code>options (contrasts = c("contr.helmert", "contr.treat"))
  A &lt;- factor( rep(c(-1,+1), 32))
  B &lt;- factor( rep(rep(c(-1, +1), rep(2,2)), 16))
  C &lt;- factor( rep(rep(c(-1, +1), rep(4,2)),8))
  D &lt;- factor( rep(c(-1, +1), rep(8,2)))
  E &lt;- factor(rep(c(-1,+1),rep(16,2)))
  F &lt;- factor(rep(c(-1,+1),rep(32,2)))
  G &lt;- factor(c(1,-1,-1,  1,  -1, 1,  1,  -1, -1, 1,  1,  -1, 1   ,-1 ,-1 ,1  ,1  ,-1 ,-1 ,1  ,-1 ,1  ,1  ,-1 ,-1 ,1  ,1  ,-1,    1   ,-1,    -1, 1   ,1  ,-1,    -1, 1,  -1, 1,  1,  -1, -1, 1   ,1  ,-1 ,1  ,-1 ,-1 ,1  ,1  ,-1 ,-1 ,1  ,-1 ,1  ,1  ,-1 ,-1 ,1  ,1  ,-1,    1,  -1, -1, 1))
  H &lt;- factor(c(1 ,-1 ,-1,    1   ,-1,    1,  1,  -1, -1, 1,  1,  -1, 1,  -1, -1, 1,  -1, 1,  1,  -1, 1,  -1, -1, 1,  1,  -1, -1, 1   ,-1,    1,  1,  -1, -1, 1,  1,  -1, 1,  -1, -1, 1,  1,  -1, -1, 1,  -1, 1,  1,  -1, 1,  -1, -1, 1,  -1, 1,  1,  -1, -1, 1,  1,  -1, 1,  -1, -1, 1))
  response &lt;-c(1492.868,  1436.853,   1885.51,    1874.33,    1663.626,   1510.596,   1858.447,   1973.903,   1838.914,   1843.337,   1990.952,   2111.174,   1899.739,   1950.174,   2193.745,   2202.168,   1557.929,   1410.439,   1899.71,    1794.309,   1606.785,   1631.428,   1856.971,   1920.209,   1902.78,    1912.863,   2130.872,   2207.799,   1928.437,   1999.139,   2326.517,   2218.633,   1362.776,   1622.451,   1756.323,   1675.851,   1627.086,   1477.928,   1904.337,   1970.514,   1958.033,   1714.306,   2089.961,   2215.401,   1770.97,    1937.336,   2256.069,   2088.461,   1371.945,   1588.166,   1825.187,   1833.408,   1591.959,   1559.9, 1860.908,   1948.155,   1945.024,   1914.496,   2110.565,   2256.448,   1883.67,    2041.186,   2354.319,   2094.562)
  
  
  data.df &lt;-data.frame(A,B,C,D,E,F,response)
  
  
  plotting.lm &lt;- lm(response ~ A*B*C*D*E*F*G*H, data = data.df)
  summary(plotting.lm)
  </code></pre>
  
  <p>The code could run straightway in R.</p>