table of Contents
There are 4 kinds of bases in DNA, namely ATCG, where the symbols "A" and "T" are complementary, and the symbols "C" and "G" are complementary, now given a DNA sequence, find his complement DNA sequence, write function DNA_strand (dna)
Branch structure
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")
dictionary
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")
function
def DNA_strand(str):
table = ''.maketrans('ATGC','TACG')
print(str.translate(table))
DNA_strand("ATTGC")
DNA_strand("AAAAA")
String replace method
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')
