打卡9：perl grep/map

while (<>) {
        @d=grep {/$_/} @b;-----------------注意此处的$_已经是grep中的$_了，不是while的。
        $l=@d;
        if ($l==0) {
                push (@b,$_);
        }
}

while(my $line=<>){
  @d = grep{ $line ne $_} @b;
  push @d,$line;
}

my @b=();
my @d=();
#my %a;
while (<>) {
        @d=grep {/$_/} @b;
        $l=@d;
        print "1:l=$l:d=@d:b=@b;cu=$_n";


        if ($l==0) {
                push (@b,$_);
        }
}

3

map
print map {"$_n";} 0..9;?
表示计算.
不是输入而是将结果放到数组中.
然后用print将数组中的内容print出来

===================================

find 递归

#!/opt/exp/bin/perl -w
use strict;
use warnings;
use File::Find;

my ($size,$dircnt,$filecnt) = (0,0);
sub process {
my $file = $File::Find::name;
if (-d $file) {
$dircnt++;
}
else {
$filecnt++;
$size += -s $file;
}
print "line17:$filen";
}
find(&;process,'.');
print "$filecnt files,$dircnt directory. $size bytes. ";

自己的理解：

#!/opt/exp/bin/perl -w
use strict;
use warnings;
sub lsr($) {
    sub lsr;
    my $cwd = shift;
    local *DH;
    if (!opendir(DH,$cwd)) {
        warn "Cannot opendir $cwd: $! $^E";
        return undef;
    }
    foreach (readdir(DH)) {
        if ($_ eq '.' || $_ eq '..') {
            next;
        }
        my $file = $cwd.'/'.$_;
        if (!-l $file && -d _) {
            $file .= '/';
            lsr($file);
        }
       # process($file,$cwd);
        process($file);
    }
    closedir(DH);
}
my ($size,0);

sub process($$) {
    my $file = shift;
    print $file,"n";
    if (substr($file,length($file)-1,1) eq '/') {
        $dircnt++;
    }
    else {
        $filecnt++;
        $size += -s $file;
    }
}
lsr('.');
print "$filecnt files,$dircnt directory. $size bytes.n";

#!/opt/exp/bin/perl -w
use strict;
use warnings;
sub lsr_s($) {
    my $cwd = shift;
    my @dirs = ($cwd.'/');
    my ($dir,$file);
    while ($dir = pop(@dirs)) {
        local *DH;
        if (!opendir(DH,$dir)) {
            warn "Cannot opendir $dir: $! $^E";
            next;
        }
        foreach (readdir(DH)) {
            if ($_ eq '.' || $_ eq '..') {
                next;
            }
            $file = $dir.$_;         
            if (!-l $file && -d _) {
                $file .= '/';
                push(@dirs,$file);
            }
           # process($file,$dir);
            process($file);
        }
        closedir(DH);
    }
}
my ($size,0);
sub process($$) {
    my $file = shift;
    print $file,1) eq '/') {
        $dircnt++;
    }
    else {
        $filecnt++;
        $size += -s $file;
    }
}
lsr_s('.');
print "$filecnt files,$dircnt directory. $size bytes.n";