perl的文件句柄不仅支持普通文件, 还支持管道,今天需要统计一个fastq文件中的序列数和碱基数,而NGS的fastq文件一般都是gzip压缩的,所以
需要读取压缩文件中的内容,代码如下:
my ($fastq) = @ARGV:
my ($reads, $bases) = cal_sequence_info($fastq);
print qq{$reads\t$bases\n}; sub cal_sequence_info {
my $fastq = shift;
my $file_handle = $fastq =~ /gz$/ ? qq{$fastq} : qq{gzip -dc $fastq |};
open FASTQ, $file_handle or die "Can't open $fastq\n";
my ($reads, $bases);
while (my $readid = <FASTQ>) {
my $quality = <FASTQ>;
my $comment = <FASTQ>;
my $sequence = <FASTQ>;
chomp($sequence);
$reads++;
$bases += length $sequence;
}
close FASTQ;
return ($reads, $bases);
}
直接利用linux中的管道, 这样可以方便的读取压缩文件中的内容