为什么我只得到第一个捕获组?
问题描述:
(https://*.com/a/2304626/6607497 和 https://*.com/a/37004214/6607497 没有帮助我)
(https://*.com/a/2304626/6607497 and https://*.com/a/37004214/6607497 did not help me)
在 Linux 中分析 /proc/stat
的问题 我开始编写一个小实用程序,但我无法按照我想要的方式获取捕获组.代码如下:
Analyzing a problem with /proc/stat
in Linux I started to write a small utility, but I can't get the capture groups the way I wanted.
Here is the code:
#!/usr/bin/perl
use strict;
use warnings;
if (open(my $fh, '<', my $file = '/proc/stat')) {
while (<$fh>) {
if (my ($cpu, @vals) = /^cpu(\d*)(?:\s+(\d+))+$/) {
print "$cpu $#vals\n";
}
}
close($fh);
} else {
die "$file: $!\n";
}
例如,通过这些输入行,我得到了输出:
For example with these input lines I get the output:
> cat /proc/stat
cpu 2709779 13999 551920 11622773 135610 0 194680 0 0 0
cpu0 677679 3082 124900 11507188 134042 0 164081 0 0 0
cpu1 775182 3866 147044 38910 135 0 15026 0 0 0
cpu2 704411 3024 143057 37674 1272 0 8403 0 0 0
cpu3 552506 4025 136918 38999 160 0 7169 0 0 0
intr 176332106 ...
0
0 0
1 0
2 0
3 0
所以匹配确实有效,但我没有将捕获组放入 @vals
(perls 5.18.2 和 5.26.1).
So the match actually works, but I don't get the capture groups into @vals
(perls 5.18.2 and 5.26.1).
答
替换
while (<$fh>) {
if (my ($cpu, @vals) = /^cpu(\d*)(?:\s+(\d+))+$/) {
与
while (<$fh>) {
my @vals;
if (my ($cpu) = /^cpu(\d*)(?:\s+(\d+)(?{ push(@vals, $^N) }))+$/) {
做我想做的事(需要 perl 5.8 或更高版本).
does what I wanted (requires perl 5.8 or newer).