如何以编程方式生成多个 Perl 文件句柄？

发布于 2024-08-17 13:05:21 字数 165 浏览 2 评论 0原文

Perl 有没有办法以编程方式生成文件句柄？

我想同时打开十个文件并使用由（常量名称+数字）组成的文件句柄写入它们。例如：

 print const_name4  "data.."; #Then print the datat to file #4

原文

Is there any way in Perl to generate file handles programmatically?

I want to open ten files simultaneously and write to them by using file handle which consists of (CONST NAME + NUMBER). For example:

 print const_name4  "data.."; #Then print the datat to file #4

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颜漓半夏 2024-08-24 13:05:21

您可以将文件句柄直接粘贴到未初始化的数组槽中。

my @handles;
for my $number (0 .. 9) {
    open $handles[$number], '>', "data$number";
}

不要忘记打印到数组中的句柄的语法略有不同：

print $handles[3] $data;    # syntax error
print {$handles[3]} $data;  # you need braces like this

You can stick filehandles straight into an uninitialised array slot.

my @handles;
for my $number (0 .. 9) {
    open $handles[$number], '>', "data$number";
}

Don't forget that the syntax for printing to a handle in an array is slightly different:

print $handles[3] $data;    # syntax error
print {$handles[3]} $data;  # you need braces like this

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想你只要分分秒秒 2024-08-24 13:05:21

带有一点 IO::File< /a> 和 map 你也可以这样做：

use IO::File;

my @files = map { IO::File->new( "file$_", 'w' ) } 0..9;

$files[2]->print( "writing to third file (file2)\n" );

With a bit of IO::File and map you can also do this:

use IO::File;

my @files = map { IO::File->new( "file$_", 'w' ) } 0..9;

$files[2]->print( "writing to third file (file2)\n" );

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染年凉城似染瑾 2024-08-24 13:05:21

如今，您可以将文件句柄分配给标量（而不是使用表达式（如您的示例所示）），因此您只需创建一个数组并用它们填充它即可。

my @list_of_file_handles;
foreach my $filename (1..10) {
    open my $fh, '>', '/path/to/' . $filename;
    push $list_of_file_handles, $fh;
}

当然，您可以使用变量代替，但它们是一种令人讨厌的方法，我'从来没有见过使用数组或哈希不是更好的选择的时候。

These days you can assign file handles to scalars (rather than using expressions (as your example does)), so you can just create an array and fill it with those.

my @list_of_file_handles;
foreach my $filename (1..10) {
    open my $fh, '>', '/path/to/' . $filename;
    push $list_of_file_handles, $fh;
}

You can, of course, use variable variables instead, but they are a nasty approach and I've never seen a time when using an array or hash wasn't a better bet.

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