title: r merge data with a corresponding without loss data
body: <p>I have a dataset with a column "country" abbreviated, and an other dataset with the country full name correspondind like that :</p>
  
  <p>FR   France GR   Germany CH   China IT   Italia ES   Spain</p>
  
  <p>I would like to know if it was possible to replace in the column "country" the abbreviation by the country full name using this table, without use a loop ?</p>
  
  <p>I already tried to merge and join but i lose data, because some rows in my dataset have not always a country information, and i don't want to lose rows, and if possible not use a loop. I think it's possible but i don't know..</p>
  
  <p>if someone know something about that</p>