[R] help in removal of fixed pattern

D. Schruth dschruth at u.washington.edu
Sun Dec 4 01:39:35 CET 2011


A great function for extracting pattern matches is 'm()'

library(caroline)
vect <- m('([xX][0-9])',df$Input)
toupper(vect)  #in case you really want all upper case x's

It does the hard work of using 'sub' to remove the non-matching parts 
(sub, grep, regexpr, etc aren't very good for this sort of thing)

It also can return a data.frame if you have multiple patterns you wish to 
match in each string vector element.

-Dave


On Fri, 2 Dec 2011, arunkumar1111 wrote:

> Hi
>
> I have column name as given below
>
> If the variable is in log(X1 + 1) pattern it should be removed and i need
> only X1
>
> Input
> log(x1 + 1)
> x2
> log(X3 +1)
>
> Expected Output X1 X2 X3
>
> Please help me
>
>
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