我怎样才能模拟“grep -B”？ Perl 中的功能？

发布于 2024-12-17 23:22:01 字数 428 浏览 0 评论 0原文

我一直在寻找一种解决方案，允许我搜索数组的行，如果字符串匹配，则将该行和前两行推入数组中。使用 grep 命令似乎可以轻松完成此操作。但是，我无法让它发挥作用。这就是我所拥有的：

sub ipsearch {
    my $ip = $_[0];
    my @IPVSCONFIG =  grep (/\W+virtual\s$ip\s/, @RAWDATA);
}

是否可以将“-B 2”语法添加到 grep 命令中？我已经尝试了这种语法的几种形式，但我无法让它工作：

@IPVSCONFIG =  grep -B 2 (/\W+virtual\s$ip\s/, @RAWDATA);

请让我知道这是否可能，以及正确的语法应该是什么。如果您有任何其他建议，请告诉我。

感谢您的帮助！

原文

I have been searching for a solution that allows me to search the lines of an array, and if a string match is made, push that line and the 2 previous lines into an array. It seems this would be easily done using the grep command. However, I cannot get this to work. This is what I have:

sub ipsearch {
    my $ip = $_[0];
    my @IPVSCONFIG =  grep (/\W+virtual\s$ip\s/, @RAWDATA);
}

Is it possible to add the "-B 2" syntax to the grep command? I've tried several forms of this syntax but I cannot get it to work:

@IPVSCONFIG =  grep -B 2 (/\W+virtual\s$ip\s/, @RAWDATA);

Please let me know if this is even possible, and what the correct syntax should be. If you have any other suggestions, please let me know.

Thanks for the help!

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勿忘心安 2024-12-24 23:22:01

诀窍是识别发生匹配的行，然后识别周围的相关索引：

获取匹配的索引：

my @matchedIndices = grep { $RAWDATA[$_] =~ /\W+virtual\s$ip\s/ } 2 .. $#RAWDATA;

获取周围的索引：

my @wantedIndices  = map { ( $_-2 .. $_ ) } @matchedIndices;

并获取一个数组切片：

my @IPVSCONFIG = @RAWDATA[ @wantedIndices ];

将其完全放入 Schwartzian 变换中：

my @IPVCONFIG = map  { @RAWDATA[$_-2..$_] }
                grep { $RAWDATA[$_] =~ /\W+virtual\s$ip\s/ }
                2 .. $#RAWDATA ;

绝对是一个比传统命令行grep -B 2！

The trick is to identify the lines where the match occurs, then identify the relevant indices around:

Get the matched indices:

my @matchedIndices = grep { $RAWDATA[$_] =~ /\W+virtual\s$ip\s/ } 2 .. $#RAWDATA;

Get the indices around:

my @wantedIndices  = map { ( $_-2 .. $_ ) } @matchedIndices;

And take an array slice:

my @IPVSCONFIG = @RAWDATA[ @wantedIndices ];

Putting it altogether in a Schwartzian transform:

my @IPVCONFIG = map  { @RAWDATA[$_-2..$_] }
                grep { $RAWDATA[$_] =~ /\W+virtual\s$ip\s/ }
                2 .. $#RAWDATA ;

Definitely a much busier solution than the traditional command-line grep -B 2!

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不及他 2024-12-24 23:22:01

子例程的基本版本。我假设您想在完成后返回该列表。未经测试。

sub ipsearch {
    my $ip = shift;
    my @IPVSCONFIG = (); # no matches should be empty list, not undef
    my @buffer = ()      # to avoid undef warnings
    for (@RAWDATA) {
        push @buffer, $_;
        shift @buffer if @buffer > 3;
        if (/\W+virtual\s$ip\s/) {
            push @IPVSCONFIG, @buffer;
            @buffer = ();
        }
    }
    return @IPVSCONFIG;
}

A basic version of your subroutine. I assume you wanted to return the list when done with it. Untested.

sub ipsearch {
    my $ip = shift;
    my @IPVSCONFIG = (); # no matches should be empty list, not undef
    my @buffer = ()      # to avoid undef warnings
    for (@RAWDATA) {
        push @buffer, $_;
        shift @buffer if @buffer > 3;
        if (/\W+virtual\s$ip\s/) {
            push @IPVSCONFIG, @buffer;
            @buffer = ();
        }
    }
    return @IPVSCONFIG;
}

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