title: Changing numbers in a string r
body: <p>I have a huge data frame. However, I have similar IDs and these were different observations. What I am trying to do is change the last/last two digit(s) in the column ID. So  for ID alnfru_00001 in row 5 should be alnfru_00006 and so on. this sequence is seen right throughout the data frame even with other IDs. Can anyone provide some assistance? </p>
  
  <pre><code>                ID          PFT        area
          1    alnfru_00001 alnfru Yukon_Delta
          2    alnfru_00002 alnfru Yukon_Delta
          3    alnfru_00003 alnfru Yukon_Delta
          4    alnfru_00004 alnfru Yukon_Delta
          5    alnfru_00001 alnfru Yukon_Delta
          6    alnfru_00002 alnfru Yukon_Delta
          7    alnfru_00003 alnfru Yukon_Delta
          8    alnfru_00004 alnfru Yukon_Delta
          9    alnfru_00005 alnfru Yukon_Delta....................................
  
          18   alnfru_00001 alnfru Yukon_Delta
          19   alnfru_00002 alnfru Yukon_Delta
          20   alnfru_00003 alnfru Yukon_Delta
          21   alnfru_00004 alnfru Yukon_Delta
          22   alnfru_00001 alnfru Yukon_Delta
          23   alnfru_00002 alnfru Yukon_Delta
          24   alnfru_00003 alnfru Yukon_Delta
          25   alnfru_00004 alnfru Yukon_Delta
  
  The data frame should look like this 
  
  
              ID          PFT        area
      1    alnfru_00001 alnfru Yukon_Delta
      2    alnfru_00002 alnfru Yukon_Delta
      3    alnfru_00003 alnfru Yukon_Delta
      4    alnfru_00004 alnfru Yukon_Delta
      5    alnfru_00005 alnfru Yukon_Delta
      6    alnfru_00006 alnfru Yukon_Delta
      7    alnfru_00007 alnfru Yukon_Delta
      8    alnfru_00008 alnfru Yukon_Delta
      9    alnfru_00009 alnfru Yukon_Delta....................................
  
      18   alnfru_00010 alnfru Yukon_Delta
      19   alnfru_00011 alnfru Yukon_Delta
      20   alnfru_00012 alnfru Yukon_Delta
      21   alnfru_00013 alnfru Yukon_Delta
      22   alnfru_00014 alnfru Yukon_Delta
      23   alnfru_00015 alnfru Yukon_Delta
      24   alnfru_00016 alnfru Yukon_Delta
      25   alnfru_00017 alnfru Yukon_Delta
  </code></pre>