引用如下形式声明：
引用名前用$，之后用[]。
$ref_to_AoA = [
[ "fred", "barney", "pebbles", "bambam", "dino", ],
[ "george", "jane", "elroy", "judy", ],
[ "homer", "bart", "marge", "maggie", ],
# assign to our array, an array of array references
@AoA = (
[ "fred", "barney", "pebbles", "bambam", "dino", ],
[ "george", "jane", "elroy", "judy", ],
[ "homer", "bart", "marge", "maggie", ],
say $AoA[2][1];
$ref_to_AoA = [
[ "fred", "barney", "pebbles", "bambam", "dino", ],
[ "george", "jane", "elroy", "judy", ],
[ "homer", "bart", "marge", "maggie", ],
print_AoA();
my @tmp = (1, 2, 3, 4);
push @AoA, [@tmp]; # 因为数组AoA第一列需要的是引用，而@tmp是数组，直接赋值会出错。[]表示返回@tmp的引用，即把@tmp的引用push到@AoA最后一行，二维数组行数加1.
print_AoA();
push @AoA, @tmp;
print_AoA();
#$AoA[0] = @tmp; #$AoA[0]是scalar型，而@tmp是list型，所以用默认把tmp的个数赋给$AoA[0]，即$AoA[0]=4;
$AoA[0] = [@tmp]; #overwirte
print_AoA();
use v5.14; # needed for implicit deref of array refs by array ops
push $AoA[0], "wilma", "betty"; # 在5.14版本之前不能通过，因为以前规定push的第一参数必须为数组。在新版本中当$AoA[0]中存在引用时可以通过，但无引用时不正确。
print_AoA();
my $aref = undef;
#push $aref, qw/some value/; # 出错：Not an ARRAY reference
my $aref = [@tmp];
push $aref, qw/some value/; # 正确，因为aref此时不是个空引用
print "$aref : @$aref\n";
for $aref ( @AoA ) # $aref只是第一列里面的引用，要想访问整行必须加@，又$访问级别比@高，所以（）可以省略。
say "\t [ @$aref ],";
for my $i (0 .. $#AoA){
say "elt $i is @{$AoA[$i]}";
for my $i (0 .. $#AoA){
for my $j (0 .. $#{$AoA[$i]}){
say "elt $i, $j is $AoA[$i][$j]\n";
my @newAoA = ();
for (my $startx= my $i = 1; $i<=5; $i++){
for(my $starty = my $j = 2; $j<=4; $j++){
$newAoA[$i - $startx][$j - $starty] = $AoA[$i][$j];
#一个循环简单写法
for (my $x = 1; $x<=5; $x++){
push @newAoA, [@{$AoA[i]}[2 .. 4]];
sub splice_2D{
my $lrr = shift;
my($x_l, $x_h,
$y_l, $y_h) = @_;
return map(
[ @{$lrr -> [$_]} {$y_l .. $y_h}]
)$x_l .. $x_h;
@newAoA = splice_2D(\@AoA, 1=>5, 2=>4);
Author: visaya fan <visayafan[AT]gmail.com or visayafan[AT]163.com>
Date: 2011-10-29 15:00:34
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