R命令以增量替代

Question

I would like to replace below:

[1] "annotated_SRR7059136_CD39-.txt" "annotated_SRR7059137_CD39+.txt"
[3] "annotated_SRR7059138_CD39-.txt" "annotated_SRR7059139_CD39+.txt"
[5] "annotated_SRR7059140_CD39-.txt" "annotated_SRR7059141_CD39+.txt"
[7] "annotated_SRR7059142_CD39-.txt" "annotated_SRR7059143_CD39+.txt"

into

[1] "1_CD39-.txt" "1_CD39+.txt"
[3] "2_CD39-.txt" "2_CD39+.txt"
[5] "3_CD39-.txt" "3_CD39+.txt"
[7] "4_CD39-.txt" "4_CD39+.txt"

So far, I've tried running this

x<- sub("annotated_SRR70591.*_","\\1",sampleFiles)

But I am getting

[1] "CD39-.txt" "CD39+.txt" "CD39-.txt" "CD39+.txt" "CD39-.txt" "CD39+.txt"
[7] "CD39-.txt" "CD39+.txt"

instead of what I wanted. Any help would be much appreciated. Thanks!

Answer 1

We can use rep and seq to generate the numbers and paste them together.

paste0(rep(seq(length(sampleFiles)/2), each = 2), "_", 
           sub("annotated_SRR70591.*_","\\1",sampleFiles))

#[1] "1_CD39-.txt" "1_CD39+.txt" "2_CD39-.txt" "2_CD39+.txt" "3_CD39-.txt" 
#[6] "3_CD39+.txt" "4_CD39-.txt" "4_CD39+.txt"

---

For better understanding breaking down the steps,

rep(seq(length(sampleFiles)/2), each = 2) #gives
#[1] 1 1 2 2 3 3 4 4

and

sub("annotated_SRR70591.*_","\\1",sampleFiles) #gives
[1] "CD39-.txt" "CD39+.txt" "CD39-.txt" "CD39+.txt" "CD39-.txt" "CD39+.txt"
[7] "CD39-.txt" "CD39+.txt"