blocks|key|1323469|text|我会这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1323470|my+$file+=+"index.html";
my+$document+=+do+{
++++local+$/+=+undef;
++++open+my+$fh,+"<",+$file
++++++++or+die+"could+not+open+$file:+$!";
++++<$fh>;
};|code-block|syntax|javascript|1323471|请注意open的三参数版本的用法。它比旧的两个(或一个)参数版本要安全得多。还要注意词法文件句柄的使用。出于许多原因，词法文件句柄比旧的无字变体更好。我们在这里利用了其中的一个:当它们超出范围时就会关闭。|1323472|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I would do it like this:

<pre><code>my $file = "index.html";
my $document = do {
 local $/ = undef;
 open my $fh, "&lt;", $file
 or die "could not open $file: $!";
 &lt;$fh&gt;;
};
</code></pre>

Note the use of the three-argument version of open. It is much safer than the old two- (or one-) argument versions. Also note the use of a lexical filehandle. Lexical filehandles are nicer than the old bareword variants, for many reasons. We are taking advantage of one of them here: they close when they go out of scope.

blocks|key|1538768|text|使用File::Slurp|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1538769|use+File::Slurp;
my+$text+=+read_file('index.html');|code-block|syntax|javascript|1538770|Yes,+even+you+can+use+CPAN。|1538771|entityMap|0|LINK|mutability|MUTABLE|url|https://metacpan.org/module/File::Slurp|1|http://www.perlmonks.org/?node_id=693828^0|2|B|0|0|0|0|Q|1|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]|$1|K|3|-4|5|6|7|13|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

With <a href="https://metacpan.org/module/File::Slurp" rel="noreferrer">File::Slurp</a>:

<pre><code>use File::Slurp;
my $text = read_file('index.html');
</code></pre>

<a href="http://www.perlmonks.org/?node_id=693828" rel="noreferrer">Yes, even you can use CPAN</a>.

blocks|key|1538727|text|所有的帖子都是稍微不那么地道的。这个成语是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1538728|open+my+$fh,+'<',+$filename+or+die+"error+opening+$filename:+$!";
my+$data+=+do+{+local+$/;+<$fh>+};|code-block|syntax|javascript|1538729|大多数情况下，不需要将$/设置为undef。|offset|length|style|CODE|1538730|entityMap^0|0|0|G|5|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

All the posts are slightly non-idiomatic. The idiom is:

<pre><code>open my $fh, '&lt;', $filename or die "error opening $filename: $!";
my $data = do { local $/; &lt;$fh&gt; };
</code></pre>

Mostly, there is no need to set $/ to <code>undef</code>.

blocks|key|1538666|text|一种简单的方法是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1538667|while+(<FILE>)+{+$document+.=+$_+}|code-block|syntax|javascript|1538668|另一种方法是更改输入记录分隔符"$/“。您可以在本地裸块中执行此操作，以避免更改全局记录分隔符。|1538669|{
++++open(F,+"filename");
++++local+$/+=+undef;
++++$d+=+<F>;
}|1538670|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

A simple way is:

<pre><code>while (&lt;FILE&gt;) { $document .= $_ }
</code></pre>

Another way is to change the input record separator "$/". You can do it locally in a bare block to avoid changing the global record separator.

<pre><code>{
 open(F, "filename");
 local $/ = undef;
 $d = &lt;F&gt;;
}
</code></pre>

blocks|key|1323520|text|要么将$/设置为undef+(参见jrockway的答案)，要么将文件的所有行连接起来：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1323521|$content+=+join('',+<$fh>);|code-block|syntax|javascript|1323522|在任何支持标量的Perl版本上，建议对文件句柄使用标量。|1323523|entityMap^0|3|2|8|5|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

Either set <code>$/</code> to <code>undef</code> (see jrockway's answer) or just concatenate all the file's lines:

<pre><code>$content = join('', &lt;$fh&gt;);
</code></pre>

It's recommended to use scalars for filehandles on any Perl version that supports it.

blocks|key|1323616|text|另一种可能的方式是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1323617|open+my+$fh,+'<',+"filename";
read+$fh,+my+$string,+-s+$fh;
close+$fh;|code-block|syntax|javascript|1323618|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Another possible way:

<pre><code>open my $fh, '&lt;', "filename";
read $fh, my $string, -s $fh;
close $fh;
</code></pre>

blocks|key|1538804|text|您只获得菱形运算符<FILE>的第一行，因为您在标量上下文中对其进行计算：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1538805|$document+=+<FILE>;+|code-block|syntax|javascript|1538806|在列表/数组上下文中，菱形运算符将返回文件的所有行。|1538807|@lines+=+<FILE>;
print+@lines;|1538808|entityMap^0|9|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

You're only getting the first line from the diamond operator <code>&lt;FILE&gt;</code> because you're evaluating it in scalar context:

<pre><code>$document = &lt;FILE&gt;; 
</code></pre>

In list/array context, the diamond operator will return all the lines of the file. 

<pre><code>@lines = &lt;FILE&gt;;
print @lines;
</code></pre>

blocks|key|1538855|text|open+f,+"test.txt"
$file+=+join+'',+<f>|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1538856|<f>+-返回文件中的行数组(如果$/的默认值为"\n")，然后join+''将此数组放入。|unstyled|offset|length|style|CODE|1538857|entityMap^0|0|0|3|H|2|O|4|W|7|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]|$G|Q|H|R|I|J]|$G|S|H|T|I|J]|$G|U|H|V|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|W|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>open f, "test.txt"
$file = join '', &lt;f&gt;
</code></pre>

<code>&lt;f&gt;</code> - returns an array of lines from our file (if <code>$/</code> has the default value <code>"\n"</code>) and then <code>join ''</code> will stick this array into.

blocks|key|1323687|text|我会以最简单的方式来做，这样任何人都可以理解发生了什么，即使有更聪明的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1323688|my+$text+=+"";
while+(my+$line+=+<FILE>)+{
++++$text+.=+$line;
}|code-block|syntax|javascript|1323689|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I would do it in the simplest way, so anyone can understand what happens, even if there are smarter ways:

<pre><code>my $text = "";
while (my $line = &lt;FILE&gt;) {
 $text .= $line;
}
</code></pre>

blocks|key|1538937|text|我不知道这是不是很好的做法，但我曾经用过：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1538938|($a=<F>);|code-block|syntax|javascript|1538939|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I don't know if it's good practice, but I used to use this:

<pre><code>($a=&lt;F&gt;);
</code></pre>

blocks|key|1538884|text|您可以简单地创建子例程：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1538885|#Get+File+Contents
sub+gfc
{
++++open+FC,+@_[0];
++++join+'',+<FC>;
}|code-block|syntax|javascript|1538886|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You could simply create a sub-routine:

<pre><code>#Get File Contents
sub gfc
{
 open FC, @_[0];
 join '', &lt;FC&gt;;
}
</code></pre>

I'm trying to open an .html file as one big long string. This is what I've got:

<pre><code>open(FILE, 'index.html') or die "Can't read file 'filename' [$!]\n"; 
$document = &lt;FILE&gt;; 
close (FILE); 
print $document;
</code></pre>

which results in: 

<pre><code>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN
</code></pre>

However, I want the result to look like: 

<pre><code>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"&gt;
&lt;html&gt;
&lt;head&gt;
&lt;meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"&gt;
</code></pre>

This way I can search the entire document more easily.

In Perl, how can I read an entire file into a string?

Perl

我正在尝试打开一个.html文件作为一个大的长字符串。这就是我得到的：open(FILE, 'index.html') or die "Can't read file 'filename' [$!]\n"; $document = <FILE>; close (FILE); print $document;这会导致：<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML

问在Perl中，如何将整个文件读入字符串？
EN

回答 11

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问在Perl中，如何将整个文件读入字符串？EN

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