我有一个巨大的fasta文件,但我只需要提取它的一部分,如果我知道我的序列的开始和结束碱基对坐标。此外,它应该在快速格式与60 bp每行的长度。这是我的尝试,请让我知道,如果看起来OK和任何建议,以改善它是欢迎的。
from Bio import SeqIO
inFile = open('full_chr.fa','r')
fw=open("part.fa",'w')
line_width = 60
for record in SeqIO.parse(inFile,'fasta'):
fw.write(">" + record.id + "n")
fww = (str(record.seq[600130000:602000000]) + 'n')
for i in xrange(0,len(fww),line_width):
fw.write(str(fww[i:i+line_width]) + 'n')
fw.close()
就这么简单:
from Bio import SeqIO
record = SeqIO.read("Chromosome.fas", "fasta")
with open("output.fas", "w") as out:
SeqIO.write(record[100:500], out, "fasta")
SeqIO.write
已经使用60个字符长度的换行。如果要操作换行,请使用FastaWriter
对象。这是一个80 bp行的例子:
from Bio import SeqIO
from Bio.SeqIO.FastaIO import FastaWriter
record = SeqIO.read("Chromosome.fas", "fasta")
with open("output.fas", "w") as out:
writer = FastaWriter(out, wrap=80)
writer.write_header()
writer.write_record(record[100:500])
writer.write_footer()