如何將字符串分解成重疊的集合的3

Question

如果我有多個字符串，如：

skhdsfiiuwkncyeuhrsl 
sdskkjheocbsill 
sldkjflsdkjb 

我怎麼能輸出程序是重疊的三胞胎，例如，我希望它輸出：

skh, khd, hds, ..., rsl 
sds, dsk, skk, ..., ill 
sld, ldk, dkj, ..., kjb 

Answer 1

從this answer獲得靈感，這裏是一個班輪：

strings <- c("skhdsfiiuwkncyeuhrsl", 
"sdskkjheocbsill", 
"sldkjflsdkjb") 

sapply(strings, function(x) substring(x, seq(1,nchar(x)-2,1), seq(3,nchar(x),1))) 

# $skhdsfiiuwkncyeuhrsl 
# [1] "skh" "khd" "hds" "dsf" "sfi" "fii" "iiu" "iuw" "uwk" "wkn" "knc" "ncy" "cye" "yeu" "euh" 
# [16] "uhr" "hrs" "rsl" 

# $sdskkjheocbsill 
# [1] "sds" "dsk" "skk" "kkj" "kjh" "jhe" "heo" "eoc" "ocb" "cbs" "bsi" "sil" "ill" 

# $sldkjflsdkjb 
# [1] "sld" "ldk" "dkj" "kjf" "jfl" "fls" "lsd" "sdk" "dkj" "kjb" 

Answer 2

substring作品：

x = c("skhdsfiiuwkncyeuhrsl", "sdskkjheocbsill", "sldkjflsdkjb", "ab") 
n = 3 
lapply(x, function(z) 
    if ((nc <- nchar(z)) >= n) 
    substring(z, seq(1, nc - n + 1), seq(n, nc)) 
    else 
    character(0) 
) 

這給

[[1]] 
[1] "skh" "khd" "hds" "dsf" "sfi" "fii" "iiu" "iuw" "uwk" "wkn" "knc" "ncy" 
[13] "cye" "yeu" "euh" "uhr" "hrs" "rsl" 

[[2]] 
[1] "sds" "dsk" "skk" "kkj" "kjh" "jhe" "heo" "eoc" "ocb" "cbs" "bsi" "sil" 
[13] "ill" 

[[3]] 
[1] "sld" "ldk" "dkj" "kjf" "jfl" "fls" "lsd" "sdk" "dkj" "kjb" 

[[4]] 
character(0) 

Answer 3

a <- "skhdsfiiuwkncyeuhrsl" 
b <- "sdskkjheocbsill" 
c <- "sldkjflsdkjb" 

make_triplets <- 
    function(X){ 
    nTriplets <- length(2:(nchar(X)-1)) 
    triplets <- character(nTriplets) 
    for(i in 2:(nchar(X)-1)){ 
     triplets[i-1] <- substr(X, i - 1, i + 1) 
    } 
    return(triplets) 
    } 
make_triplets(a) 

make_triplets(b) 

make_triplets(c)