python dna

DNA互补序列的生成可以使用多种方法。一种方法是使用Python自带的replace()函数来进行替换操作，代码示例如下：

def DNA_complement4(sequence):
    sequence = sequence.replace('A', 't')
    sequence = sequence.replace('T', 'a')
    sequence = sequence.replace('G', 'c')
    sequence = sequence.replace('C', 'g')
    sequence = sequence.replace('a', 'T')
    sequence = sequence.replace('t', 'A')
    sequence = sequence.replace('g', 'C')
    sequence = sequence.replace('c', 'G')
    return sequence

另一种方法是使用str.maketrans()函数和str.translate()函数来进行字符转换，代码示例如下：

def DNA_complement2(sequence):
    trantab = str.maketrans('ACGTacgtRYMKrymkVBHDvbhd', 'TGCAtgcaYRKMyrkmBVDHbvdh')
    string = sequence.translate(trantab)
    return string

还有一种原始方法是使用多个if分支来进行字符替换，代码示例如下：

def DNA_complement3(sequence):
    sequence_list = list(sequence)
    string = []
    for base in sequence_list:
        if base == "A":
            string.append('T')
        elif base == "T":
            string.append('A')
        elif base == "G":
            string.append('C')
        elif base == "C":
            string.append('G')
        elif base == "a":
            string.append('t')
        elif base == "t":
            string.append('a')
        elif base == "g":
            string.append('c')
        elif base == "c":
            string.append('g')
    return ''.join(string)