dna_to_rna.py

import string


dna_letters = "ATGC" #All possible DNA letter
rna_letters = "UACG" #All possible RNA Letters

dna = input("Please enter you DNA string: ") #Gets DNA Input
dna = dna.upper()  #Changes DNA to uppercase if not already
print(f"Your DNA sequence is: {dna}") #Prints the DNA Sequence

rna = "" #Creates a blank variable

for letter in dna: #For ever letter in DNA it loops
    for i in range(4): #Loops 4 times since there is only 4 possible letters
        if letter == dna_letters[i]: #If hat index is the same as one of the letters
            rna += rna_letters[i] #Adds the RNA version of it to the variable


print(f"Your messenger RNA strand is: {rna}") #Prints the Final RNA sequence