Solutions to the first 6 ROSALIND (http://rosalind.info) problems in Python

1_DNA.py

# 1 Jan 2013

if __name__ == '__main__':
    s = raw_input()
    # f(char) counts the instances of `char` in `s`
    f = lambda c: len(filter(lambda i: i == c, s))
    print ' '.join(map(str, [f('A'), f('C'), f('G'), f('T')]))

2_RNA.py

# 1 Jan 2013

if __name__ == '__main__':
    s = raw_input()
    print s.replace('T', 'U')

3_REVC.py

# 1 Jan 2013

if __name__ == '__main__':
    s = raw_input()
    c = lambda i: {'A': 'T', 'T': 'A', 'C': 'G', 'G': 'C'}[i]
    s = map(c, s)
    s.reverse()
    print ''.join(s)

4_GC.py

# 1 Jan 2013

if __name__ == '__main__':
    gc = lambda s: float(len(filter(lambda c: c == 'G' or c == 'C', s))) / len(s)
    data = []
    name = ''
    strand = ''
    while True:
        try:
            line = raw_input()
            if line[0] == '>':
                if len(name): data.append([strand, name])
                name = line[1:]
                strand = ''
            else:
                strand += line
        except EOFError:
            if len(name): data.append([strand, name])
            break

    data = map(lambda e: [gc(e[0]), e[1]], data)
    data.sort()
    data.reverse()

    print data[0][1]
    print str(data[0][0] * 100) + '%'

5_HAMM.py

# 1 Jan 2013

if __name__ == '__main__':
    a = raw_input()
    b = raw_input()
    print len([1 for i in range(len(a)) if a[i] != b[i]])

6_SUBS.py

# 1 Jan 2013

if __name__ == '__main__':
    strand = raw_input()
    seq = raw_input()

    print ' '.join([str(i+1) for i in range(len(strand)) if strand[i:i+len(seq)] == seq])