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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