title: Adding all values of a variable in R
body: <p>I don't know how to word the title exactly, so I will just do my best to explain below... Sorry in advance for the .csv format.</p>
  
  <p>I have the following example dataset:</p>
  
  <pre><code>print(data)
  
        ID Tag  Flowers
  1     1  6871  1
  2     2  6750  1
  3     3  6859  1
  4     4  6767  1
  5     5  6747  1
  6     6  6261  1
  7     7  6750  1
  8     8  6767  1
  9     9  6812  1
  10   10  6746  1
  11   11  6496  4
  12   12  6497  1
  13   13  6495  4
  14   14  6481  1
  15   15  6485  1
  </code></pre>
  
  <p>Notice that in Lines 2 and 7, the tag 6750 appears twice. I observed one flower on plant number 6750 on two separate days, equaling two flowers in its lifetime. Basically, I want to add every flower that occurs for tag 6750, tag 6767, etc throughout ~100 rows. Each tag appears more than once, usually around 4 or 5 times.</p>
  
  <p>I feel like I need to apply the unlist function here, but I'm a little bit lost as to how I should do so.</p>