Perl 在脚本中进行就地编辑(而不是单行) [英] Perl in place editing within a script (rather than one liner)

问题描述

所以，我习惯于 perl -i 使用 perl，就像我使用 sed 和就地编辑一样.

So, I'm used to the perl -i to use perl as I would sed and in place edit.

perlvar 中 $^I 的文档:

$^I就地编辑扩展的当前值.使用 undef 禁用就地编辑.

$^I The current value of the inplace-edit extension. Use undef to disable inplace editing.

好的.所以这意味着我可能会在脚本中进行就地"编辑?

OK. So this implies that I can perhaps mess around with 'in place' editing in a script?

我遇到的问题是:

如果我跑:

perl -pi -e 's/^/fish/' test_file

然后解析它:

BEGIN { $^I = ""; }
LINE: while (defined($_ = <ARGV>)) {
    s/^/fish/;
}
continue {
    die "-p destination: $!\n" unless print $_;
}

现在 - 如果我想在脚本中使用 $^I，请说:

Now - if I were to want to use $^I within a script, say to:

 foreach my $file  ( glob "*.csv" ) {
     #inplace edit these files - maybe using Text::CSV to manipulate? 
 }

我如何启用"这种情况?这是更改 $_ (如 s/something/somethingelse/ 默认情况下所做的)并让 perl 隐式打印它的问题吗?还是有其他事情发生?

How do I 'enable' this to happen? Is it a question of changing $_ (as s/something/somethingelse/ does by default) and letting perl implicitly print it? Or is there something else going on?

我的主要问题是 - 我可以进行应用 CSV 转换(或 XML 调整或类似操作)的就地编辑"吗?

My major question is - can I do an 'in place edit' that applies a CSV transform (or XML tweak, or similar).

我很感激我可以打开单独的文件句柄、读取/打印等.我想知道是否还有其他方法.(即使它只是在特定情况下有用).

I appreciate I can open separate file handles, read/print etc. I was wondering if there was another way. (even if it is only situationally useful).

推荐答案

由 -i 命令行选项或通过设置 $^ 启用的就地编辑行为I 仅适用于 ARGV 文件句柄.这意味着文件必须在命令行中命名或 @ARGV 必须在程序中设置

The edit-in-place behaviour that is enabled by the -i command-line option or by setting $^I works only on the ARGV file handle. That means the files must either be named on the command line or @ARGV must be set up within the program

此程序会将所有 CSV 文件中的所有小写字母更改为大写字母.请注意，我已将 $^I 设置为非空字符串，建议您在测试时这样做，以便保留原始数据文件

This program will change all lower-case letters to upper-case in all CSV files. Note that I have set $^I to a non-null string, which is advisable while you are testing so that your original data files are retained

use strict;
use warnings;

our $^I = '.bak';

while ( my $file = glob '*.csv' ) {

  print "Processing $file\n";

  our @ARGV = ($file);

  while ( <ARGV> ) {
     tr/a-z/A-Z/;
     print;
  }
}

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