Perl 中的单引号和双引号有什么区别? [英] What's the difference between single and double quotes in Perl?

问题描述

在 Perl 中，' 和 " 有什么区别?

In Perl, what is the difference between ' and " ?

例如，我有 2 个变量，如下所示:

For example, I have 2 variables like below:

$var1 = '(';
$var2 = "(";

$res1 = ($matchStr =~ m/$var1/);
$res2 = ($matchStr =~ m/$var2/);

$res2 语句抱怨 Unmatched ( 在正则表达式 m 中的 HERE 标记之前.

推荐答案

双引号使用变量扩展.单引号不要

Double quotes use variable expansion. Single quotes don't

在双引号字符串中，您需要对某些字符进行转义以防止它们被不同地解释.在单引号字符串中你没有(反斜杠除外，如果它是字符串中的最后一个字符)

In a double quoted string you need to escape certain characters to stop them being interpreted differently. In a single quoted string you don't (except for a backslash if it is the final character in the string)

my $var1 = 'Hello';

my $var2 = "$var1";
my $var3 = '$var1';

print $var2;
print "
";
print $var3;
print "
";

这将输出

Hello
$var1

Perl Monks 对此有很好的解释这里

Perl Monks has a pretty good explanation of this here

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