Finding the complementry strand of DNA-CodePudding

I'm given the following DNA string:

mydna = 'AGUGGCUAUUACUACAUGCCGAAGUUCCUUAAAUUUAACUUACCAGGCUUAACCGGAUGAUGAUUAUUAUUACCUUAAUUUUA'

How can I get the DNA string's complement?

CodePudding user response：

Here's a quick one liner that does the job:

''.join([{'A': 'U', 'U': 'A', 'C': 'G', 'G': 'C'}[i.upper()] for i in mydna])

It iterates through every character in the original string and then replaces the values.

CodePudding user response：

You can use str.maketrans:

translation = str.maketrans("AUCG", "UAGC")
print(mydna.translate(translation))

This outputs:

UCACCGAUAAUGAUGUACGGCUUCAAGGAAUUUAAAUUGAAUGGUCCGAAUUGGCCUACUACUAAUAAUAAUGGAAUUAAAAU

CodePudding user response：

No fancy stuff:

original_strand = 'AGUGGCUAUUACUACAUGCCGAAGUUCCUUAAAUUUAACUUACCAGGCUUAACCGGAUGAUGAUUAUUAUUACCUUAAUUUUA'
new_strand = ''

for char in original_strand: # for every character in the string...
    if char == 'A':
        replace_with = 'U'
    elif char == 'U':
        replace_with = 'A'
    elif char == 'C':
        replace_with = 'G'
    elif char == 'G':
        replace_with = 'C'

    new_strand  = replace_with

print(new_strand)