删除向量中至少 N 个连续值的序列

Question

这是我的问题。我有大量积极数据。我的目标是删除向量中至少有 N 个连续重复值的序列(所有重复值必须严格 > 0)。

我编写了一个可以运行的程序，如下所示: X 是我的数值向量； N为重复序列的最小长度。

rmpParNASerieRepetee <- function(X, N)
{
    X_ <- paste("T", paste(X, collapse="T"), "T", sep="")
    ind.parcours <- 1
    ind.sup <- c()

    # Loop on the values
    while ( ind.parcours <= (length(X)-N+1) )
    {
        # indices of my sequence of N values
        deb <- ind.parcours
        fin <- ind.parcours + N-1

        # sequence of N values to search in the vector
        serie  <- X[deb:fin]
        serie_ <- paste("T", paste(serie, collapse="T"), "T", sep="")


        borne <- 1*(ind.parcours < (length(X)-N+1)) + 0*(ind.parcours == (length(X)-N+1))
        if (sum(X[(length(X)-N+1):length(X)]==serie)==3) borne <- 0

        # split my string vector by my sequence vector of N values and count the pieces of result
        if ( length(unlist(strsplit(X_, serie_)))-1 > borne && length(which(serie!=0))>=N)
        { ind.sup <- unique(c(ind.sup, deb:fin)) }
        ind.parcours <- ind.parcours+1
    }
    if (length(ind.sup !=0)) { X[ind.sup] <- NA }

    list_return <- list(X=X, Ind.sup=unique(sort(ind.sup)))
    return (list_return)
}

我认为我的函数确实不是最优的(对于 92,000 个值的向量，N=18，计算时间为 1:15)。而且我必须执行此步骤 1600 次...大约需要 3 个月...

有人有更好的主意吗？

示例:

x <- c(1,2,3,4,0,4,1,2,3,8,9,1,2,3,4,0)
N <- 3
# (1,2,3) is a sequence of 3 elements which is repeated
# (1,2,3,4) is  sequence of 4 elements which is repeated
# no other sequence of length at least 3 repeats
# my result should also be :
# NA NA NA NA 0 4 NA NA NA 8 9 NA NA NA NA 0
# The result of my program is :
# $X
# [1] NA NA NA NA  0  4 NA NA NA  8  9 NA NA NA NA  0
#$Ind.sup
# [1]  1  2  3  4  7  8  9 12 13 14 15

Answer 1

一种方法:

f <- function(X, N)
{
 .rle <- rle(sort(X))
 res <- .rle$values[.rle$lengths >= N]
 res <- res[res > 0]
 inds <- X %in% res
 X[inds] <- NA 
 list(X = X, Ind = which(inds)) 
}

#> f(X, 3)
#$X
# [1] NA NA NA NA  0  0  0  0 NA NA NA NA NA NA  8  9 NA NA NA NA NA NA  0  0  0
#
#$Ind
# [1]  1  2  3  4  9 10 11 12 13 14 17 18 19 20 21 22