regex - How to find the strings DO NOT starts with "2012" using regular expressions? -


hi have date format strings, , want find out ones not start "2012" using regular expression (in r). have tried grep("^[^2012]",dataset) did not work. , have tried grep("^[^2][^0][^1][^2]",dataset) , still did not work. pattern question? appreciated.

you can use ! in front of grepl:

 x[ !grepl("^2012", x) ]

grep("^[^2012] , ...) reject values started of digits. (i'm not sure why second 1 didn't work.) gustav's suggestion works if specify perl=true:

x[ grep("^(?!2012)", x, perl=true) ]

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