I cannot process chars

Question

I am writing code that translates a DNA sequence! The program imports a string called shortDNA (for example ATCGGA) and has to translate it (specifically to TAGCCT), but for some reason it gives the shortDNA string that it imports(in this case ATTCGGA)! what is wrong with my code?

for (int i = 0; i < shortDNA.length(); i++) {
            char ch = shortDNA.charAt(i);
            if (ch=='A'){
                ch='T';
            }
            else if (ch=='T'){
                ch='A';
            }
            else if (ch=='G'){
                ch='C';
            }
            else if (ch=='C'){
                ch='G';
            }
        }

@guy I don't thing switch case is a good idea! what do you have in mind? — Gamio, Jan 17 '16 at 14:16
@Gamio It won't solve your problem, its basically what you did but the compiler improve the performance. [example](http://stackoverflow.com/a/6705977/5168011) (there are many more, search for "if else or switch" in your favorite search engine). — Guy, Jan 17 '16 at 14:23
@guy I checked it out switch has exactly the same problem! I can't understand why — Gamio, Jan 17 '16 at 14:25
@Gamio As I said, it won't solve your problem, just good practice. — Guy, Jan 17 '16 at 14:27
And as for your problem, you don't show enough code to solve it as @Marvin said. — Guy, Jan 17 '16 at 14:27
@guy I think I solved it! I built another string which saves the translated sequence — Gamio, Jan 17 '16 at 14:30

score 0 · Accepted Answer · answered Jan 17 '16 at 14:38

0

Instead of setting a character variable which is discarded, I assume you want to use this character to build a new String.

StringBuilder sb = new StringBuilder();
for (char ch : dna.toCharArray()) {
    switch (ch) {
        case 'A': sb.append('T'); break;
        case 'T': sb.append('A'); break;
        case 'G': sb.append('C'); break;
        case 'C': sb.append('G'); break;
    }
}
String dna2 = sb.toString();

answered Jan 17 '16 at 14:38

Peter Lawrey

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thanks a lot, that's what I proposed at the comments above! – Gamio Jan 17 '16 at 14:47

I cannot process chars

1 Answers1