小编sid*_*com的帖子

我在Mail :: IMAPClient中找到了这个.在什么地方$_在$SEARCH_KEYS{ uc($_) }从何而来？

sub _quote_search {
    my ( $self, @args ) = @_;
    my @ret;
    foreach my $v (@args) {
        if ( ref($v) eq "SCALAR" ) {
            push( @ret, $$v );
        }
        elsif ( exists $SEARCH_KEYS{ uc($_) } ) {
            push( @ret, $v );
        }
        elsif ( @args == 1 ) {
            push( @ret, $v );    # <3.17 compat: caller responsible for quoting
        }
        else {
            push( @ret, $self->Quote($v) );
        }
    } …

Rakudo:有没有列出所有尚未使用的功能的地方？

删除相应的符号表条目后,为什么要从"$ n"和"$ m"中获取值？

#!/usr/bin/env perl
use warnings;
use 5.012;

package Foo;

our $n = 10;
our $m = 20;

delete $Foo::{'n'};
delete $Foo::{'m'};

say $n; # 10
say $m; # 20

#!/usr/local/bin/perl
use warnings;
use 5.014;
use Mojolicious::Lite;
use DBI;

# ...

get '/choose' => sub {
    my $self = shift;
    my $lastname = $self->param( 'lastname' );
    my $sth = $dbh->prepare( "SELECT id, firstname, birthday FROM $table WHERE lastname == ?" );
    $sth->execute( $lastname );
    my @rows;
    while ( my $row = $sth->fetchrow_hashref ) {
        push @rows, { id => $row->{id}, firstname => $row->{firstname}, lastname => $lastname, birthday => $row->{birthday} };
    }
    if ( not @rows ) {
        $self->redirect_to( 'new_entry' ); …

有没有一种更短的方式来在JavaScript中写这个？

    var data = [];
    var table = document.getElementById( 'address' );
    var rows = table.getElementsByTagName( 'tr' );
    for ( var x = 0; x < rows.length; x++ ) {
        var td = rows[x].getElementsByTagName( 'td' );
        for ( var y = 0; y < td.length; y++ ) {
            var input = td[y].getElementsByTagName( 'input' );
            for ( var z = 0; z < input.length; z++ ) {
                data.push( input[z].id );
            }
        }
    }

如何动态加载OO样式的模块？

#!/usr/bin/env perl6
use v6;

my $r = prompt ':';

if $r {
    require Text::CSV;          # Error:
    my $csv = Text::CSV.new;    # Could not find symbol '&CSV'
} else {
    require File::Temp <&tempfile>;
    my ( $filename , $filehandle ) = tempfile; # this works
}

如何将一个数组插入一个数组中？

在Perl 5中，我可以这样进行：

use Data::Dumper;
my @aoa = ( [ 'a', 'A' ], [ 'c', 'C' ] );
splice( @aoa, 1, 0, [ 'b', 'B' ] );
print Dumper \@aoa;

（在Perl 6 splice中使替换变平）

参考：

但请注意，qr//标量在创建时已经受到祝福，因此ref qr/.../可能会返回Regexp。

“可能”是否意味着，这ref qr/.../也可能返回除Regexp

这些中最好的还是最差的方法之一？

利用范围:

my $cache = CHI->new( driver => 'File', expires_in => 3600 );

sub one {
    if ( my $data = $cache->get( 'key_one' ) ) {
    # ...
}

sub two {
    if ( my $data = $cache->get( 'key_two' ) ) {
    # ...
}

传递对象作为参数:

my $cache = CHI->new( driver => 'File', expires_in => 3600 );

sub one {
    my ( $cache ) = @_;
    if ( my $data = $cache->get( 'key_one' ) ) {
    # ...
}

sub …

检查SQLite表是否超过100,000行的最快方法是什么？

测试表有26列和200,000,000行.

SELECT COUNT(*) FROM ( SELECT * FROM table LIMIT 100001 )

花了0.27秒.

以下三个需要12分半钟

SELECT COUNT(*) FROM table
SELECT COUNT(*) FROM table LIMIT 100001
SELECT CASE WHEN COUNT(Id) >= 100000 THEN 1 ELSE 0 END FROM table