Articles by Shreyes

Editing/Adding factor levels in R

April 29, 2013 | Shreyes

I was trying to change few levels in my factor variable by simply coercing characters on that factor variable but it dint seem to work.
data(iris)<br>iris$Species[c(50:120)] <- rep("Random", 71)<br>
## Warning: invalid factor level, NAs generated<br>
iris$Species<br>
##   [1] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##   [8] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [15] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [22] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [29] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [36] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [43] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [50] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br><br>##  [57] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br>##  [64] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br><br>##  [71] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br>##  [78] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br><br>##  [85] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br>##  [92] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br><br>##  [99] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br>## [106] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br><br>## [113] <NA>      <NA>      <NA>      <NA>      <NA>      <NA>      <NA>     <br>## [120] <NA>      virginica virginica virginica virginica virginica virginica<br>## [127] virginica virginica virginica virginica virginica virginica virginica<br>## [134] virginica virginica virginica virginica virginica virginica virginica<br>## [141] virginica virginica virginica virginica virginica virginica virginica<br>## [148] virginica virginica virginica<br>## Levels: setosa versicolor virginica<br><br>
Well, I did find a way to find a work around for that by doing this:
iris$Species <- as.character(iris$Species)<br>iris$Species[c(50:120)] <- rep("Random", 71)<br>iris$Species <- as.factor(iris$Species)<br>iris$Species<br>
##   [1] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##   [8] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [15] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [22] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [29] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [36] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [43] setosa    setosa    setosa    setosa    setosa    setosa    setosa   <br>##  [50] Random    Random    Random    Random    Random    Random    Random   <br>##  [57] Random    Random    Random    Random    Random    Random    Random   <br>##  [64] Random    Random    Random    Random    Random    Random    Random   <br>##  [71] Random    Random    Random    Random    Random    Random    Random   <br>##  [78] Random    Random    Random    Random    Random    Random    Random   <br>##  [85] Random    Random    Random    Random    Random    Random    Random   <br>##  [92] Random    Random    Random    Random    Random    Random    Random   <br>##  [99] Random    Random    Random    Random    Random    Random    Random   <br>## [106] Random    Random    Random    Random    Random    Random    Random   <br>## [113] Random    Random    Random    Random    Random    Random    Random   <br>## [120] Random    virginica virginica virginica virginica virginica virginica<br>## [127] virginica virginica virginica virginica virginica virginica virginica<br>## [134] virginica virginica virginica virginica virginica virginica virginica<br>## [141] virginica virginica virginica virginica virginica virginica virginica<br>## [148] virginica virginica virginica<br>## Levels: Random setosa virginica<br>
This problem annoyed ... [Read more...]

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