ruby 生成哈希值_Ruby中的哈希

r囧r小猫 2022-12-06 15:47 187阅读 0赞

ruby 生成哈希值

[Arrays][] are not the only way to manage collections of variables in [Ruby][]. Another type of collection of variables is the *hash*, also called an associative array. A hash is like an array in that it's a variable that stores other variables. However, a hash is unlike an array in that the stored variables are not stored in any particular order, and they are retrieved with a key instead of by their position in the collection.

[数组][Arrays]并不是管理[Ruby][]中变量集合的唯一方法。 变量集合的另一种类型是*hash* ，也称为关联数组。 哈希就像一个数组，因为它是一个存储其他变量的变量。 但是，哈希与数组不同，因为存储的变量没有以任何特定顺序存储，而是使用键而不是通过它们在集合中的位置来检索它们。

## 使用键/值对创建哈希 **(** Create a Hash With Key/Value Pairs **)** ##

A hash is useful to store what are called *key/value pairs*. A key/value pair has an identifier to signify which variable of the hash you want to access *and* a variable to store in that position in the hash. For example, a teacher might store a student's grades in a hash. Bob's grade would be accessed in a hash by the key "Bob" and the variable stored at that location would be Bob's grade.

散列对于存储所谓的*键/值对*很有用。 键/值对具有一个标识符，表示要访问的哈希变量， *以及*一个存储在哈希中该位置的变量。 例如，老师可能将学生的成绩存储在哈希中。 Bob的成绩将通过键“ Bob”以散列方式访问，并且存储在该位置的变量将是Bob的成绩。

A hash variable can be created the same way as an array variable. The simplest method is to create an empty hash object and fill it with key/value pairs. Note that the index operator is used, but the student's name is used instead of a number.

可以使用与数组变量相同的方式来创建哈希变量。 最简单的方法是创建一个空的哈希对象，并用键/值对填充它。 请注意，使用的是索引运算符，但使用的是学生的姓名而不是数字。

Remember that hashes are unordered, meaning there is no defined beginning or end as there is in an array. So, you cannot append to a hash. Values are simply inserted into the hash using the index operator.

请记住，哈希是无序的，这意味着没有定义的开始或结束，就像数组中一样。 因此，您不能追加到哈希。 只需使用索引运算符将值插入哈希即可。

#!/usr/bin/env ruby
    grades = Hash.new
    grades["Bob"] = 82
    grades["Jim"] = 94
    grades["Billy"] = 58
    puts grad

## 散列文字 **(** Hash Literals **)** ##

Just like arrays, hashes can be created with hash [literals.][] Hash literals use the curly braces instead of square brackets and the key value pairs are joined by **=>**. For example, a hash with a single key/value pair of Bob/84 would look like this: **\{ "Bob" => 84 \}**. Additional key/value pairs can be added to the hash literal by separating them with commas. In the following example, a hash is created with the grades for a number of students.

就像数组一样，可以使用散列[文字][literals.]创建散列[。][literals.] 散列文字使用大括号而不是方括号，并且键值对由**=>连接** 。 例如，具有Bob / 84的单个键/值对的哈希看起来像这样： **\{“ Bob” => 84\}** 。 可以通过使用逗号将其他键/值对添加到哈希文字中。 在以下示例中，将创建一个哈希值，其中包含许多学生的成绩。

#!/usr/bin/env ruby
    grades = { "Bob" => 82,
    "Jim" => 94,
    "Billy" => 58
    }
    puts grad

## 在哈希中访问变量 **(** Accessing Variables in the Hash **)** ##

There may be times when you must access each variable in the hash. You can still loop over the variables in the hash using the *each* loop, though it won't work the same way as using the *each* loop with array variables. Because a hash is unordered, the order in which *each* will loop over the key/value pairs may not be the same as the order in which you inserted them. In this example, a hash of grades will be looped over and printed.

有时您必须访问哈希中的每个变量。 您仍然可以使用*each*循环遍历散列中的变量，尽管它的工作方式不同于将*each*循环与数组变量一起使用。 由于哈希是无序的，因此*每个*哈希在键/值对上的循环顺序可能与您插入键/值对的顺序不同。 在此示例中，将遍历并打印成绩的哈希值。

#!/usr/bin/env ruby
    grades = { "Bob" => 82,
    "Jim" => 94,
    "Billy" => 58
    }
    grades.each do|name,grade|
    puts "#{name}: #{gra

> 翻译自: [https://www.thoughtco.com/how-to-create-hashes-2908196][https_www.thoughtco.com_how-to-create-hashes-2908196]

ruby 生成哈希值

[Arrays]: https://www.thoughtco.com/how-to-create-arrays-in-ruby-2908192
[Ruby]: https://www.thoughtco.com/ruby-programming-4133469
[literals.]: https://www.thoughtco.com/fun-with-strings-example-code-2034322
[https_www.thoughtco.com_how-to-create-hashes-2908196]: https://www.thoughtco.com/how-to-create-hashes-2908196