Perl变量声明中的$，@，％之间有什么区别？ [英] What are the differences between $, @, % in Perl variable declaration?

问题描述

示例：

my $some_variable;
my @some_variable;
my %some_variable;

我知道， @ 似乎适合数组， $ 表示原始数组，这完全正确吗？
％有什么用途？

I know, @ seems to be for array, $ for primitive, is it totally right? What is % for?

推荐答案

其中之一Perl的优点是它带有内置的手册。键入以下命令：

One of the nice things about Perl is that it comes with a built in manual. Type in the following command:

perldoc perlintro

并查看 Perl变量类型部分。您还可以在有关Perl变量的 perldoc.perl.org 部分中看到此内容。

and take a look at the section Perl variable types. You can also see this on line with the perldoc.perl.org section on Perl variables.

快速概述：

• $ foo 是 scalar 变量。它可以包含单个值，该值可以是字符串，数字等。


• @foo 是 array 。数组可以容纳多个值。您可以使用索引访问这些值。例如， $ foo [0] 是数组的第一个元素，而 $ foo [1] 是数组的第二个元素，依此类推。（数组通常以零开头）。



• ％foo 是 hash ，就像一个数组，因为它可以容纳多个值，但哈希是键控数组。例如，我有一个密码哈希，称为％password 。这由用户名键入，值是用户的密码。例如：

• $foo is a scalar variable. It can hold a single value which can be a string, numeric, etc.
• @foo is an array. Arrays can hold multiple values. You can access these values using an index. For example $foo[0] is the first element of the array and $foo[1] is the second element of the array, etc. (Arrays usually start with zero).

• %foo is a hash, this is like an array because it can hold more than one value, but hashes are keyed arrays. For example, I have a password hash called %password. This is keyed by the user name and the values are the user's password. For example:

$ password {Fred} = swordfish;
$ password {Betty} =秘密；

$password{Fred} = "swordfish"; $password{Betty} = "secret";

$ user = Fred;
print用户$ user的密码为$ password {$ user} \n； ＃打印出箭鱼
$ user = Betty;
print用户$ user的密码为$ password {$ user} \n； ＃打印出秘密

$user = "Fred"; print "The Password for user $user is $password{$user}\n"; #Prints out Swordfish $user = "Betty"; print "The Password for user $user is $password{$user}\n"; #Prints out secret

请注意，当您在散列中引用单个值时或 array ，则使用美元符号。

Note that when you refer to a single value in a hash or array, you use the dollar sign. It's a little confusing for beginners.

我建议您拿一本骆驼书。 骆驼书是学习Perl ，并且是对该语言的出色介绍。

I would recommend that you get the Llama Book. The Llama Book is Learning Perl and is an excellent introduction to the language.

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