How to append an entire array to a string in C#

Question

I'm trying to recreate a program I made with C++ into a C# windows form program I have the bulk of it done. There's one small thing that's keeping the program from working like it should.

My program is a bionformatics program that allows the user to either enter a string/sequence of DNA or RNA characters and the program converts it into the corresponding protein/amino acid and prints out an amino acid/protein for every codon the program sees. So if I input "AAA GGG CCC" it prints out "Lysine Glycine Proline".

This is the snippet of code I'm having trouble with in the C++ version

for (i=0; i<numberOfCodons;i++)
{
 endIndex=beginIndex+3;
 codon="";
 {
 //here is where I'm having the trouble converting this to C# and have it cout the write
 //way 
 codon.append(RNA.substr(beginIndex,endIndex-beginIndex));
 }
 for (k=0;k<64;k++)
 {
 if(codon==codons[k])
 {
 //here is where I'm having the trouble converting this to C# and have it cout the write way
 //like I metioned previously AAA GGG CCC couts Lysine Glycine Proline 
 protein.append(aminoAcids[k]); 
 } 
 }
 beginIndex+=3;
}
cout<<protein<<endl;
protein.clear();

here's what I have in c# so far

private void Tranlate_Click(object sender, EventArgs e)
{
 numberOfCodons = rnaLength / 3;
 beginIndex = 0;
 richTextBox2.AppendText("Total Number Of codons are: ");
 richTextBox2.AppendText(numberOfCodons.ToString());
 richTextBox2.AppendText("\n");
 for (i = 0; i < numberOfCodons; i++)
 {
 endIndex = beginIndex + 3;
 codon = ""; 
 {
 // these are the two possible conversions of the C++ code that dont work at all for me******
 // codon.AppendText(RNA.Substring(beginIndex, endIndex - beginIndex));
 codon=(RNA.Substring(beginIndex, endIndex - beginIndex));
 }
 for (k = 0; k < 64; k++)
 {
 if (codon == codons[k])
 {
 //supposed to print out all the coresponding amino acids from the array and it will only print out one amino acid (Lysine)*******
 //protein.AppendText(aminoAcids[k]);
 protein = (aminoAcids[k]);
 }
 }
 beginIndex += 3;
 }
 richTextBox2.AppendText(protein);
 richTextBox2.AppendText("\n");
 //protein.clear();
}

Why is it doing this and how can I fix it?

Answer 1

Try to change this line inside your loop

protein = (aminoAcids[k]); 

to

protein += (aminoAcids[k]); 

The C++ version loops for 64 times and append to a string, the C# version reinitialize the string every time and ends with the last match found by the comparison if (codon == codons[k]).

The same happens with the codon string
This reinitialize it in every loop

codon=(RNA.Substring(beginIndex, endIndex - beginIndex)); 

but, in this case, I'm not sure if it is right to build a single string and then check against a string array like codons[k]

PS. While they are ininfluent on the code generated, I find your liberal use of parenthesys a bit distracting. You could write aminoAcids[k]; and codon=RNA.Substring(beginIndex, endIndex - beginIndex);. This is (in my opinion) more clear.

• Gilad Naaman: Also, consider using StringBuilder
• Steve: @GiladNaaman, not sure if, in this case, the usage of StringBuilder is really effective. See here dotnetperls.com/stringbuilder-performance .

Answer 2

Your code is a nice candidate for LINQ which is widely used in C#. If I understood the logic correctly, you could write something like:

richTextBox2.AppendText(string.Join("\n",
 Enumerable.Range(0, numberOfCodons)
 .Select(i => RNA.Substring(i * 3, i * 3 + 3))
 .Where(c => codons.Contains(c))
 .Select(c => aminoAcids[codons.IndexOf(c)])
 .ToArray())
 );