这是个经济学论坛 你不觉得你这个问题到bioconductor上去问更合适么

是要输出这样的结果吗#从第一位截取，每次截取长度为4个碱基的短串，生成一系列短串
> data1
    [,1]   [,2]   [,3]   [,4]   [,5]   [,6]   [,7]   [,8]   [,9]   [,10]  [,11]  [,12]  [,13]  [,14]  [,15]
tmp "TTTC" "CTTT" "TTTT" "GAAC" "AGAT" "GATT" "TTAG" "TGAG" "CACT" "GCGC" "TAGG" "AGTA" "TGTG" "TTGA" "ATCT"
tmp "GGAA" "TCTG" "CAAC" "TCGG" "ATGG" "CCGT" "CTCA" "AGTA" "AGCA" "ACAA" "CATT" "GTTG" "CTTG" "CGGC" "TTCC"
tmp "CTCT" "TTCT" "ACCT" "AATG" "GTGA" "AATT" "CGCG" "AGAG" "AACG" "ATTA" "GACA" "CGCC" "GCGC" "TGAT" "GGGC"
    [,16]  [,17]  [,18]  [,19]  [,20]  [,21]  [,22]  [,23]  [,24]  [,25]
tmp "CCAA" "CCCT" "CGGA" "ACAT" "AGTC" "GTTG" "CTCT" "TGCG" "GACT" "GAGA"
tmp "CGGG" "TGTC" "GCTA" "AGCG" "TTTA" "AAAA" "GTTG" "TTAG" "GATT" "AACC"
tmp "AGGA" "GTGT" "TTGC" "ACTC" "GATG" "AATC" "CCTC" "GACT" "GGGA" "CCGG"
#查找要查找短串"GTTG"在所有短串中的位置
> result
[[1]]
[1] 21

[[2]]
[1] 12 22

[[3]]
integer(0)


代码如下

lapply(gregexpr("ATCG", c("ATCGATCG","ATCGTCGA", "AAAAAAAA")), function(x) x[x %% 4 == 1])