rosalind练习题一

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)