awk:有什么方法可以访问匹配的组? [英] awk: any way to access the matched groups in action?

问题描述

我经常发现自己在动作上与模式相同，以访问输入记录的某些部分，例如

I often find myself doing the same match in the action as the pattern, to access some part of the input record, e.g.

/^Compiled from \"(.*)\"$/ {
    file_name = gensub("^Compiled from \"(.*)\"$", "\\1", "g");
    print file_name;
}

因此，regexp匹配完成了两次.有什么方法可以在不再次匹配的情况下访问操作中的\\1?

So the regexp matching is done twice. Is there any way I can access \\1 in the action without matching again?

我正试图减少模式匹配和额外的代码.

I am trying to both reduce on pattert matching and extra code.

推荐答案

不幸的是，GAWK没有使用空//的sed的结转功能.

Unfortunately, GAWK, doesn't have the carry-forward feature of sed which uses an empty //.

sed '/\(patt\)ern/ {s//new\1/}' inputfile

但是，由于变量是最近被发明的，因此您可以为之高兴！

However, you can rejoice since variables have recently been invented and they can be used for just this purpose!

BEGIN {
    pattern = "^Compiled from \"(.*)\"$"
}
$0 ~ pattern {
    file_name = gensub(pattern, "\\1", "");
    print file_name;
}

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