Python experience

Most of my education in bioinformatics used the R coding language. In my free time I have done some coding exercises to familiarize myself with python as well. Below is one of the scripts I have written as a coding exercise. It takes a users RNA string as input and translates it into the corresponding amino acid string. I’m well aware many translation tools already exist but I thought it would be a good exercise to practice writing loops.

#RNA to protein translation script

# Ask user to input RNA string
rna_string = input("Please input RNA sequence: ")

# remove newlines and whitespaces + determine length of string
rna_string_stripped = rna_string.rstrip()   
length_string = len(rna_string_stripped)

# generate position of the first nucleotide in each codon. 
numberlist = list(range(0,length_string,3))

#  create empty lists that will later be used to hold codons and amino strings.
amino_string = []
codon_list = []

# break up RNA string into codons and add codons to codon list.
for number in numberlist:
    codon_list.append(rna_string_stripped[number] + rna_string_stripped[number+1] + rna_string_stripped[number+2])

# create a codon dictionary which can be used to look up the corresponding amino acid.  
codondict ={
    'UUU': 'F',
    'UUC': 'F',
    'UUA': 'L',
    'UUG': 'L',
    'CUU': 'L',
    'CUC': 'L',
    'CUG': 'L',
    'CUA': 'L',
    'AUU': 'I',
    'AUC': 'I',
    'AUA': 'I',
    'AUG': 'M',
    'GUU': 'V',
    'GUC': 'V',
    'GUA': 'V',
    'GUG': 'V',
    'UCU': 'S',
    'UCC': 'S',
    'UCA': 'S',
    'UCG': 'S',
    'CCU': 'P',
    'CCC': 'P',
    'CCA': 'P',
    'CCG': 'P',
    'ACU': 'T',
    'ACC': 'T',
    'ACA': 'T',
    'ACG': 'T',
    'GCU': 'A',
    'GCC': 'A',
    'GCA': 'A',
    'GCG': 'A',
    'UAU': 'Y',
    'UAC': 'Y',
    'UAA': 'Stop',
    'UAG': 'Stop',
    'CAU': 'H',
    'CAC': 'H',
    'CAA': 'Q',
    'CAG': 'Q',
    'AAU': 'N',
    'AAC': 'N',
    'AAA': 'K',
    'AAG': 'K',
    'GAU': 'D',
    'GAC': 'D',
    'GAA': 'E',
    'GAG': 'E',
    'UGU': 'C',
    'UGC': 'C',
    'UGA': 'Stop',
    'UGG': 'W',
    'CGU': 'R',
    'CGC': 'R',
    'CGA': 'R',
    'CGG': 'R',
    'AGU': 'S',
    'AGC': 'S',
    'AGA': 'R',
    'AGG': 'R',
    'GGU': 'G',
    'GGC': 'G',
    'GGA': 'G',
    'GGG': 'G',
    }

# Use codon dictionary to translate codons to amino acids. 
for codon in codon_list:
    amino_string.append(codondict[codon])

#join amino acids into long long string
output = ''.join(amino_string)

print(output)