Multiple conditions in if statements in R

Question

I am trying to cut out the list of gene names that I was given. I am trying to eliminate any duplicate names that may be present, but I keep getting an error when running my code:

counter=0
i=0
j=0
geneNamesRevised=array(dim=length(geneNames))
for (i in 0:length(geneNamesRevised))
  geneNamesRevised[i]=""
geneNamesRevised
for (i in 1:length(geneNames))
  for (j in 1:length(geneNamesRevised))
    if (geneNames[i]==geneNamesRevised[j])
    {
      break
    }
    else if ((j==length(geneNamesRevised)-1) &&
             (geneNames[i]!=geneNamesRevised[j]))
    {
      geneNamesRevised[counter]=geneNames[i]
      counter++
    }

The error message is a repeating line:

the condition has a length> 1, and only the first element will be used, the condition has a length> 1, and only the first element will be used, the condition has a length> 1, and only the first element will be used

and this is an error message for the last "else if" statement having "& &".

Thank!

Answer 1

Why not just

geneNamesRevised <- unique( geneNames )

..., . duplicated, .

Answer 2

.

1) else - :) @Mohsen_Fatemi

2) , &&

3) counter ++ R

,

   for (i in 1:length(geneNames)){
     for (j in 1:length(geneNamesRevised)){
      if (geneNames[i]==geneNamesRevised[j])
      {
           break
      } else {

           if ((j==length(geneNamesRevised)-1) & (geneNames[i]!=geneNamesRevised[j]))
           {
                geneNamesRevised[counter]=geneNames[i]
                counter <- counter + 1
           }
      }
   }
}

Edit

4) for s

Answer 3

use &instead &&,

else if ((j==length(geneNamesRevised)-1) & (geneNames[i]!=geneNamesRevised[j]))