python - 从 FASTA 文件中提取基因序列？

Question

我有以下代码读取包含 10 个基因序列的 FASTA 文件并将每个序列作为矩阵返回。然而，代码似乎在最后一个序列中丢失了，我想知道为什么？

file=open('/Users/vivianspro/Downloads/rosalind_cons (5).txt', 'r')
line=file.readline()

strings = []
sequence=''
while line:
    #line=line.rstrip('\n')
    line = line.strip() #empty () automatically strips the \n
    if '>' in line:
        if sequence != "":
            strings.append(sequence)
            sequence = ""
        #sequence=line
    else:
        sequence+=line
    line=file.readline()
for s in strings:
    print(s)

Motifs = []
for seq in strings:
    Motifs.append(list(seq))

#make every symbol into an element in the list separated by ,
for s in Motifs:
    print(s) ````

Answer 1

当您看到一个新的 > 但在最后一个序列之后没有一个时，您只追加到 strings。

这是一个重构，希望它也更符合惯用语。

strings = []
sequence=''

with open('/Users/vivianspro/Downloads/rosalind_cons (5).txt', 'r') as file:
    for line in file:
        line = line.rstrip('\n')
        if line.startswith('>'):
            if sequence != "":
                strings.append(sequence)
            sequence = ""
        else:
            sequence+=line
    # After the last iteration, append once more if we have something to append
    if sequence:
        strings.append(sequence)