[英]perl: using push() on an array inside a hash
Is it possible to use Perl's push() function on an array inside a hash? 是否可以在哈希内的数组上使用Perl的push()函数?
Below is what I believe to be the offending part of a larger program that I am working on. 以下是我认为是我正在研究的较大程序的有问题的部分。
my %domains = ();
open (TABLE, "placeholder.foo") || die "cannot read domtblout file\n";
while ($line = <TABLE>)
{
if (!($line =~ /^#/))
{
@split_line = split(/\t/, $line); # splits on tabs - some entries contain whitespace
if ($split_line[13] >= $domain_cutoff)
{
push($domains{$split_line[0]}[0], $split_line[19]); # adds "env from" coordinate to array
push($domains{$split_line[0]}[1], $split_line[20]); # adds "env to" coordinate to array
# %domains is a hash, but $domains{identifier}[0] and $domains{$identifier}[1] are both arrays
# this way, all domains from one sequence are stored with the same hash key, but can easily be processed iteratively
}
}
}
Later I try to interact with these arrays using 后来我尝试使用
for ($i = 0, $i <= $domains{$identifier}[0], $i++)
{
$from = $domains{$identifier}[0][$i];
$to = $domains{$identifier}[1][$i];
$length = ($to - $from);
$tmp_seq =~ /.{$from}(.{$length})/;
print("$header"."$1");
}
but it appears as if the arrays I created are empty. 但似乎我创建的数组为空。
If $domains{$identifier}[0] is an array, then why can I not use the push statement to add an element to it? 如果$ domains {$ identifier} [0]是一个数组,那么为什么不能使用push语句向其中添加元素?
$domains{identifier}[0]
is not an array. $domains{identifier}[0]
不是数组。
$domains{identifier}[0]
is an array element, a scalar. $domains{identifier}[0]
是一个数组元素,一个标量。
$domains{identifier}[0]
is a reference to an array. $domains{identifier}[0]
是对数组的引用。
If it's 如果它是
@array
when you have an array, it's 当你有一个数组,它是
@{ ... }
when you have a reference to an array, so 当您引用数组时,
push(@{ $domains{ $split_line[0] }[0] }, $split_line[19]);
References: 参考文献:
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