R Remove row if column X is Na AND column B is not 'value'

Question

I relativity new R and R Stack Overflow, so forgive me for my poor explanation

I am trying to remove all values with in the emp_length column that are Na AND the grade column with in the same row is equal to "C" OR "B"

fullData2_empData_rm <- fullData2[!is.na(fullData2$emp_length) ,] 
          && (fullData2$grade != 'B' || fullData2$grade != 'C')

So far I have been unsuccessful

I have made a basic JavaScrip example, in case my explanation is not very good.

Thanks

const remove (row) => {
  if(row.emp_length == null && (row.grade == 'C' || row.grade == 'B'{
      removeRow()
  }else{
    keepRow()
  } 
}

Answer 1

We can remove the && and || to & and | as the &&/|| returns a single TRUE/FALSE as output

fullData2[!is.na(fullData2$emp_length) & 
        (fullData2$grade != 'B' |fullData2$grade != 'C'),]