Complement a DNA sequence

Question

Suppose I have a DNA sequence. I want to get the complement of it. I used the following code but I am not getting it. What am I doing wrong ?

s=readline()
AT         


        

Answer 1

sapply(p, switch,  "A"="T", "T"="A","G"="C","C"="G")
  A   T   C   T   C   G   G   C   G   C   G   C   A   T   C   G   C   G   T 
"T" "A" "G" "A" "G" "C" "C" "G" "C" "G" "C" "G" "T" "A" "G" "C" "G" "C" "A" 
  A   C   G   C   T   A   C   T   A   G   C 
"T" "G" "C" "G" "A" "T" "G" "A" "T" "C" "G" 

If you do not want the complementary names, you can always strip them with unname.

unname(sapply(p, switch,  "A"="T", "T"="A","G"="C","C"="G") )
 [1] "T" "A" "G" "A" "G" "C" "C" "G" "C" "G" "C" "G" "T" "A" "G" "C" "G" "C"
[19] "A" "T" "G" "C" "G" "A" "T" "G" "A" "T" "C" "G"
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