Problem
A string is simply an ordered collection of symbols selected from some alphabet and formed into a word; the length of a string is the number of symbols that it contains.
An example of a length 21 DNA string (whose alphabet contains the symbols 'A', 'C', 'G', and 'T') is "ATGCTTCAGAAAGGTCTTACG."
Given: A DNA string s
of length at most 1000 nt.
Return: Four integers (separated by spaces) counting the respective number of times that the symbols 'A', 'C', 'G', and 'T' occur in s.
Sample Dataset
AGCTTTTCATTCTGACTGCAACGGGCAATATGTCTCTGTGTGGATTAAAAAAAGAGTGTCTGATAGCAGC
Sample Output
20 12 17 21
代码：
seq="AGCTTTTCATTCTGACTGCAACGGGCAATATGTCTCTGTGTGGATTAAAAAAAGAGTGTCTGATAGCAGC"
# 第一种方法
print(seq.count("A"))
print(seq.count("C"))
print(seq.count("G"))
print(seq.count("T"))
# 第二种方法
a = 0
b = 0
c = 0
d = 0
for i in seq:
if i == "A":
a += 1
elif i == "C":
b += 1
elif i == "G":
c += 1
elif i == "T":
d += 1
print(a, b, c, d)
