unexpected behaviour of sub() / usage of regexp

Dear R users,


the way I understand the documentation of sub() and regexp the following code:



sub('[[:digit:]]{1,2}', '', '9ewww')



... should yield:

'ewww'


It returns, however:

'www'


Why is this the case? My code should just substitute 1 (minimum) or up to 2 (maximum) digits, i.e. numbers and not the 'e' in the string. Do I misinterpret something here?

Thanks for any ideas
Jannis

 sessionInfo()

R version 2.14.0 (2011-10-31)
Platform: i686-pc-linux-gnu (32-bit)

locale:
  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
  [7] LC_PAPER=C                 LC_NAME=C                 
  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base