perl实现从一个文件中随机抽取n行

源码之前，了无秘密，直接上源码：

if(@ARGV!=2){

die "Usage: $0 sample_file sample_number\n";

}

my($sample_file, $sample_number) = @ARGV;

open my $FILE, "<$sample_file" or die "Can‘t open $sample_file $!\n";

my @content = <$FILE>;

my $all_number = @content;

print STDERR "|$all_number|\n";

my %hits;

my $wl = $sample_number;

for(my $i = 0; $i < $all_number; ++$i){

if(rand($all_number-$i) < $wl){

$hits{$i} = 1;

print STDERR "$wl\n";

--$wl;

}

}

my $j = 0;

print STDERR "start\n";

foreach(@content){

print "$_" if $hits{$j};

++$j;

}

print STDERR "done.\n";

原文:http://blog.csdn.net/hongchangfirst/article/details/25126457

作者:hongchangfirst

hongchangfirst的主页:http://blog.csdn.net/hongchangfirst