目录
在DNA中有4种碱基,分别为ATCG,其中符号“A”和“T”是互补的,符号“C”和“G”是互补的,现给定一个DNA序列,求出他的互补DNA序列,编写函数 DNA_strand(dna)
分支结构
def DNA_strand(str):
str_list = list(str)
for i in range(len(str_list)):
if str_list[i] =='A':
str_list[i] = 'T'
elif str_list[i] == 'T':
str_list[i] = 'A'
elif str_list[i] == 'C':
str_list[i] = 'G'
elif str_list[i] == 'G':
str_list[i] = 'C'
print(''.join(str_list))
DNA_strand("ATTGC")
DNA_strand("AAAAA")
字典
def DNA_strand(str):
ref = {'A':'T','T':'A','C':'G','G':'C'}
print(''.join(ref[i] for i in str))
DNA_strand("ATTGC")
DNA_strand("AAAAA")
函数
def DNA_strand(str):
table = ''.maketrans('ATGC','TACG')
print(str.translate(table))
DNA_strand("ATTGC")
DNA_strand("AAAAA")
字符串replace方法
def DNA_strand(dna):
dna_dict = {'A':'T','T':'A','G':'C','C':'G'}
dna_re = ''
for i in dna:
dna_re += i.replace(i,dna_dict[i])
print(dna_re)
DNA_strand('ATTGC')
DNA_strand('AAAA')