[R] simultaneous actions of grep ???

[Marc Schwartz]

On Mon, 2007-06-25 at 17:15 +0100, Ana Patricia Martins wrote:
> Hello R-users and developers,
> 
> Once again, I'm asking for your help.
> 
> There is other way to do the same more easily for applied simultaneous
> grep???
>   
>     c<-subset(c,!rownames(c) %in% grep(".1",rownames(c),value=T))
>     c<-subset(c,!rownames(c) %in% grep(".5",rownames(c),value=T))
>     c<-subset(c,!rownames(c) %in% grep(".6",rownames(c),value=T))
>     c<-subset(c,!rownames(c) %in% grep(".99999",rownames(c),value=T))
> 
> Thanks in advance for helping me.

One question might be what other possible values can the rownames take.

For example, if you want to check for '.99999', but not for other values
containing a '9' after the decimal, something like the following should
work:

sub.c <- subset(c, 
                !rownames(c) %in% 
                grep("\\.([156])|([9]{5})", rownames(c), 
                     value = TRUE))

Otherwise, if you want to include anything with a '9' after a decimal,
the following would work:

sub.c <- subset(c, 
                !rownames(c) %in% 
                grep("\\.[1569]", rownames(c), value = TRUE))


See ?regex and the information there for some additional guidance. There
are also many regex references online, such as:

  http://www.regular-expressions.info/

BTW, it would be preferable not to use 'c' to name an object in R, since
c() is a function. While conflicts should, in general, not occur, it
eliminates such risk and makes for more easily readable code to not use
function names for objects.

HTH,

Marc Schwartz