无限循环 (The Infinite Loop) 如果条件永远不会变为假,则循环变为无限循环。 for循环传统上用于此目的。 由于不需要构成for循环的三个表达式,因此可以通过将条件表达式留空来创建无限循环。 #!/usr/local/bin/perl for( ; ; ) { printf "This loop will run forever.\n"; }
Perl Shell> foreach (0..20) { last if eof(F); print "$_: " . ; } 0: #!/usr/bin/perl -w 1: 2: use strict; 3: 4: foreach (0..20) 5: { 6: my $line = <>; 7: last unless defined $line; # exit loop if $line is not defined 8: print "$_ : $line"; 9: }...
next语句(回到当前循环头部)(等同于C里的continue) for($i=0;$i<=100;$i++){nextif(not$i%2);print"An odd number = $i\n"; } 语句块和循环语句可以设置标号,last、redo 和 next都可以带一个标号。(等价于C的loop语句) 退出perl? exit 0;代表正常退出perl。 第4学时 基本构件的堆栈:列表与数组 ...
Scripts written in Perl can implement looping, or iteration, with the while, until, and for constructs. In each case, a block of code is executed repeatedly until a loop exit condition is satisfied. The script then continues on from that point. The while Statement...
ears" if length $ear >= 10; go_outside() and play() unless $is_raining; "when" executes the statement when $_ smart matches "EXPR", and then either "break"s out if it's enclosed in a "given" scope or skips to the "next" element when it lies directly inside a "for" loop....
status) = _;);条件变量(多个条件时)这个是an yeve nt学习上面几种事件监控后必须要了解的.大家都见到上面有 anyevent->condvar;禾口 $cv->recv 这二个,condvar 是 condition variable 的简写.是指当 什么样的条件成立时的变量其实就是条件,当达到什么条件时退出事件循环.所以anyevent中没有传统事件中的loop...
问在perl中使用Test::More进行单元和集成测试-如何捕获退出调用？EN对于测试工作而言，微服务架构对于传统...
LOOP1: foreach my $n (1..3) { LOOP2: foreach my $m (1..3) { if (($n == 2) && ($m == 2)) { last LOOP1 } print "$n$m\n"; } } next文next は最も内側のループの次のループに移ります。下記の例は行頭が # で始まらない行を表示します。
You can also use "while" in a post-condition: print "LA LA LA\n" while 1; # loops forever for Exactly like C: for ($i = 0; $i <= $max; $i++) { ... } The C style for loop is rarely needed in Perl since Perl provides the more friendly list scanning "foreach" loop. ...
message($_)foreach@list; } submessage { my$m=shiftorreturn; print("$m\n"); } suberror { my$e=shift||'unkown error'; print("$0: $e\n"); exit0; } 注意注释掉的部分,写法和之前的condition语句一样。 loop.pl #!/usr/bin/perl ...