October 2022
Beginner to intermediate
390 pages
7h 5m
Chinese
Content preview from Perl语言入门（第8版）
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
202
｜
第
10
章
和另外两个操作符一样，
redo
在
5
种循环块里都可以使用，并且在循环块嵌套的情况
下只对最内层的循环起作用。
next
和
redo
之间最大的区别在于，
next
会正常继续下一次迭代，而
redo
则会重新
执行这次的迭代。下面的程序可以让你体验这三种操作符在工作方式上的区别：
foreach (1..10) {
print "Iteration number $_.\n\n";
print "Please choose: last, next, redo, or none of the above? ";
chomp(my $choice = <STDIN>);
print "\n";
last if $choice =~ /last/i;
next if $choice =~ /next/i;
redo if $choice =~ /redo/i;
print "That wasn't any of the choices... onward!\n\n";
}
print "That's all, folks!\n";
如果不键入任何字符，只是按下回车键，则循环会逐次增加计数。如果你在显示数字
4
的时候选择
last
，那么循环就会因此而结束，你将看不到数字
5
；如果你在显示数
字
4
的时候选择
next
，就会直接跳到数字
5
而不提示“
onward
”信息；如果你在显
示数字
4
的时候选择
redo
，那么会回到
4
这个数字上重来。
带标签的块
当你需要从内层对外层的循环块进行控制时，请使用标签（ ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.