这里的一个快速和肮脏的版本:
#!/usr/bin/perl
use strict;
use warnings;
my $prevLine = "";
my @others;
for(<DATA>) {
chomp;
if (/:\s*$/) { # lines ends with : and potential space after
$prevLine = $_;
} elsif (!/:/) { # line doesn't contain ':'
push(@others, $_);
} elsif ($prevLine eq "") { # this is a "x: y, z" line, nothing in buffer
print $_ . "\n";
} else { # this is a "x: y, z" line, with a previous line in buffer
print $prevLine . join(", ", @others) . "\n" . $_ . "\n";
}
}
__DATA__
alpha: beta
beta: alpha, beta
omega: beta, gamma, alpha
gamma:
alpha
beta
gamma
epsilon: alpha
输出:
alpha: beta
beta: alpha, beta
omega: beta, gamma, alpha
gamma: alpha, beta, gamma
epsilon: alpha
如果第一行不以冒号结尾,会发生什么?如果前两行不以冒号结尾? –