在數據框內分割一個序列？

Question

我有這樣一個CSV文件，

x <- read.csv("C:/Users/XXXX/Documents/XXXX/Day1_15042014/work2.csv") 
class(x) 
x$Sequence.window![enter image description here][1] 

> x$Sequence.window 

    [1] VVELRKTGGDTLEFHKFYKNFSSGLKDVVWN                 
    [2] PGLTTQGTKFGRKIVKTLAYRVKSTQPSSGN                 
    [3] EATEFYLRYYVGHKGKFGHEFLEFEFREDGK                 
    [4] LVPVVWGERKTPEIEKKGFGASSKAATSLPS                 
    [5] NMNELPEKKNSAGFIKLEDKQKLIVEMEKSV                 
    [6] PTLHFNYRYFETDAPKDVPGAPRQWWFGGGT                 
    [7] PDPTTAPMEAAKQPKKKRSRSKKCKSVNNLD                 
    [8] PAKAAKTAKVTSPAKKAVAATKKVATVATKK              

類的，這是一個數據幀。現在我想在10:22範圍內分割序列窗口（Ex [1] VVELRKTGGDTLEFHKFYKNFSSGLKDVVWN，對於所有序列，輸出應該像[1] DTLEFHKFYKNFS）。我如何在數據框中做到這一點？

Answer 1

可以使用substr功能

#dummy data 
x <- read.table(text="Sequence.window 
VVELRKTGGDTLEFHKFYKNFSSGLKDVVWN 
PGLTTQGTKFGRKIVKTLAYRVKSTQPSSGN 
EATEFYLRYYVGHKGKFGHEFLEFEFREDGK",header=TRUE,as.is=TRUE) 

#substr from 10 to 22 
substr(x$Sequence.window,start=10,stop=22) 
#[1] "DTLEFHKFYKNFS" "FGRKIVKTLAYRV" "YVGHKGKFGHEFL"