LS,
  
  I would really like to know how to count the frequency/occurrence of  chachters inside a dataset. I am working with extreemly large datasets  of forest inventory data with a large variety of different species  inside it. 
  Each row inside the dataframe represents one individual tree and the simplified dataframe looks something like this:
  
  num species dbh   
  1        sp1           30
  2        sp1          20
  3        sp2          30
  4        sp1          40
  
  I need to be able to count the number of individuals per species, so I  need a command that will return for each unique species its occurence  inside the dataframe; 
  
  [sp1]     3
  [sp2]     1
  
  After a long search through help.search() and the web I found very  little and any alternative like exporting the dataset to another  program(excel) is not really an option because the dataset is far to  large.
  
  I am using R 2.2.0 in Windows and if anyone knows a solution please help!
  
  Many sincere thanks in advance,
  
  Marco 
  
  
  
		
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