\name{mask}
\alias{mask}


\title{Mask regions on a sequence}
\description{
  Mask regions delimited by from and to on a sequence buffer. This
  function delete the reverse complement if exists (should be
  recomputed).
}
\usage{
mask(seqno = 0, from = 1, to = 0, letter = "N")
}

\arguments{
  \item{seqno}{Integer/scalar, Sequence number (buffer number)}
   \item{from, to}{Integer/scalar, Absolute addresses of the beginning and the end of the fragment,
  (1 means the first nucleotide and 0 conventionally the last one; 
  from must not be larger than to and both vectors must be the same size)}
  \item{letter}{Letter to use for masking}
}

\value{
 usually 1; NULL if error. 
}

\author{Antoine Lucas}


\seealso{See also \code{\link{posMaskedSeq}},   \code{\link{upperSeq}},  \code{\link{lowerSeq}}}
\examples{

s <- "ATGCtgTGTTagtacAATGAGTGAGAGATGTGGGTTTaAAAattt"
placeString(s,upper=FALSE,seqno=0)
mask(from=c(10,20),to=c(15,22))
getSeq()

}

\keyword{utilities}