Inserting new values into a vector requires to describe
where to insert the new values. The function "insert.values"
allows you to define the new position(s) by fractional
indices or by a logical vector.
"insert.values" <- function(x,pos.insert,x.insert){
# insert.values inserts x.insert into x at positions defined by
pos.insert
# Arguments:
# x input vector
# x.insert vector of new values to be stored
# pos.insert defines the positions of the new values in one of two
ways:
# a) pos.insert is a vector of fractional numbers of the
same length
# as x.insert: x.insert[i] will be inserted between
# x[ floor(pos.insert) ] and x[ ceiling(pos.insert) ]
# b) pos.insert is of mode logical with length(x) values
FALSE
# and length(x.insert) values TRUE. Then TRUE values
indicate
# the position of the new elements and FALSE the values
# of old ones
#
# Examples:
# > x<-1:5
# > insert.values(x, 2.5, 1000)
# [1] 1 2 1000 3 4 5
# > insert.values(x, (1:5)+.2, 1001:1005)
# [1] 1 1001 2 1002 3 1003 4 1004 5 1005
# > insert.values(x, .9, 1111)
# [1] 1111 1 2 3 4 5
# > insert.values(x, c(T,rep(F,5)), 1000)
# [1] 1000 1 2 3 4 5
# > insert.values(x, c(rep(F,5),T), 1000)
# [1] 1 2 3 4 5 1000
# > insert.values(x, rbind(rep(F,5),T), 1001:1005)
# [1] 1 1001 2 1002 3 1003 4 1004 5 1005
# pw 02/2003
if(is.logical(pos.insert)){
pos.insert <- pos.insert[pos.insert]/length(pos.insert) +
cumsum(!pos.insert)[pos.insert]
}
x<-c(x,x.insert)[order(c(seq(x),pos.insert))]
return(x)
}
Peter Wolf
--------------------------------------
Dr. Agustin Lobo wrote:
> I've searched the doc for insert
> and could not find the way to do the following,
> hope someone can help:
>
> Let's say we have a vector:
> > a
> [1] "1" "2" "3" "5" "6" "3"
>
> and we want to insert a "7" after
> any given "3", i.e., we want vector a
> to become:
>
> [1] "1" "2" "3" "7" "5" "6" "3" "7"
-------------------------------------------------------------------------------
Peter Wolf, Statistik/Informatik, Fak.f.Wiwi, Uni Bielefeld
[EMAIL PROTECTED], http://www.wiwi.uni-bielefeld.de/~wolf/wolf.html
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