秒速五厘米 2022-12-06 15:47 140阅读 0赞

glob目录点

"[Globbing][]" files (with *Dir.glob*) in Ruby allows you to select just the files you want, such as all the XML files, in a given directory. Even though *Dir.blog* is *like *regular expressions, it is not. It's very limited compared to [Ruby][]'s regular expressions and is more closely related to shell expansion wildcards.

Ruby中的“ [Globbing][] ”文件(带有*Dir.glob* )使您可以在给定目录中仅选择所需的文件，例如所有XML文件。 即使*Dir.blog* *就像*正则表达式，也不是。 与[Ruby][]的正则表达式相比，它非常受限制，并且与shell扩展通配符更紧密相关。

The opposite of globbing, iterating over all the files in a directory, can be done with the *Dir.foreach* method.

使用*Dir.foreach*方法可以完成遍历相反的操作，即遍历目录中的所有文件。

## 例 **(** Example **)** ##

The following glob will match all files ending in *.rb* in the [current directory][]. It uses a single wildcard, the asterisk. The asterisk will match zero or more characters, so any file ending in *.rb* will match this glob, including a file called simply *.rb*, with nothing before the file extension and its preceding period. The glob method will return all files that match the globbing rules as an array, which can be saved for later use or iterated over.

以下glob将匹配[当前目录][current directory]中所有以*.rb*结尾的文件。 它使用单个通配符星号。 星号将匹配零个或多个字符，因此任何以*.rb*结尾的文件都将匹配此glob，包括名为*.rb*的文件，在文件扩展名及其前一个期间之前没有任何内容。 glob方法将所有与globbing规则匹配的文件作为数组返回，可以将其保存以备后用或迭代。

#!/usr/bin/env ruby

Dir.glob('*.rb').each do|f|

puts f

end

## 通配符及更多 **(** Wildcards and More **)** ##

There are only a few wildcards to learn:

仅需学习一些通配符：

*  **\*** – Match zero or more characters. A glob consisting of only the asterisk and no other characters or wildcards will match all files in the current directory. The asterisk is usually combined with a file extension if not more characters to narrow down the search.
    
    **\*** –匹配零个或多个字符。 仅由星号组成且没有其他字符或通配符的全局名称将匹配当前目录中的所有文件。 如果没有更多字符，星号通常与文件扩展名结合使用以缩小搜索范围。
 *  **\*\*** – Match all directories recursively. This is used to descend into the directory tree and find all files in sub-directories of the current directory, rather than just files in the current directory. This wildcard is explored in the example code below.
    
    **\*\*** –递归匹配所有目录。 它用于下降到目录树中并在当前目录的子目录中查找所有文件，而不仅仅是在当前目录中的文件。 在下面的示例代码中对此通配符进行了研究。
 *  **?** – Match any one character. This is useful for finding files whose name are in a particular format. For example, 5 characters and a .xml extension could be expressed as *?????.xml*.
    
    **？** –匹配任意一个字符。 这对于查找名称具有特定格式的文件很有用。 例如，5个字符和一个.xml扩展名可以表示为*?????。xml* 。
 *  **\[a-z\]** – Match any character in the character set. The set can be either a list of characters or a range separated with the hyphen character. Character sets follow the same syntax as and behave in the same manner as character sets in regular expressions.
    
    **\[az\]** –匹配字符集中的任何字符。 该集合可以是字符列表，也可以是用连字符分隔的范围。 字符集与正则表达式中的字符集遵循相同的语法并以相同的方式运行。
 *  **\{a,b\}** – Match pattern a or b. Though this looks like a regular expression quantifier, it isn't. For example, in regular expression, the pattern *a\{1,2\}* will match 1 or 2 'a' characters. In globbing, it will match the string *a1* or *a2*. Other patterns can be nested inside of this construct.
    
    **\{a，b\}** –匹配模式a或b。 尽管这看起来像是一个正则表达式量词，但事实并非如此。 例如，在正则表达式中，模式*a \{1,2\}*将匹配1或2个'a'字符。 在遍历中，它将匹配字符串*a1*或*a2* 。 其他模式可以嵌套在此构造内部。

One thing to consider is [case sensitivity][]. It's up to the operating system to determine whether *TEST.txt* and *TeSt.TxT* refer to the same file. On Linux and other systems, these are different files. On Windows, these will refer to the same file.

要考虑的一件事是[区分大小写][case sensitivity] 。 由操作系统决定*TEST.txt*和*TeSt.TxT*是否引用相同的文件。 在Linux和其他系统上，这些是不同的文件。 在Windows上，这些将引用相同的文件。

The operating system is also responsible for the order in which the results are displayed. It may differ if you're on Windows versus [Linux][], for example.

操作系统还负责显示结果的顺序。 例如，如果您使用的是Windows vs [Linux][] ，则可能会有所不同。

One final thing to note is the *Dir\[globstring\]* convenience method. This is functionally the same as *Dir.glob(globstring)* and is also semantically correct (you are indexing a directory, much like an array). For this reason, you may see *Dir\[\]* more often than *Dir.glob*, but they are the same thing.

最后要注意的一件事是*Dir \[globstring\]*便捷方法。 这在功能上与*Dir.glob(globstring)*相同，并且在语义上也是正确的(您正在为目录建立索引，就像数组一样)。 因此，您可能比*Dir.glob*看到*Dir \[\]的*频率*更高* ，但是它们是同一回事。

## 使用通配符的示例 **(** Examples Using Wildcards **)** ##

The following example program will demonstrate as many patterns as it can in many different combinations.

以下示例程序将以许多不同的组合演示尽可能多的模式。

#!/usr/bin/env ruby

# Get all .xml files

Dir['*.xml']

# Get all files with 5 characters and a .jpg extension

Dir['?????.jpg']

# Get all jpg, png and gif images

Dir['*.{jpg,png,gif}']

# Descend into the directory tree and get all jpg images

# Note: this will also file jpg images in the current directory

Dir['**/*.jpg']

# Descend into all directories starting with Uni and find all

# jpg images.

# Note: this only descends down one directory

Dir['Uni**/*.jpg']

# Descend into all directories starting with Uni and all

# subdirectories of directories starting with Uni and find

# all .jpg images

Dir['Uni**/**/*.jpg']

> 翻译自: [https://www.thoughtco.com/using-glob-with-directories-2907832][https_www.thoughtco.com_using-glob-with-directories-2907832]

glob目录点

[Globbing]: https://www.thoughtco.com/globbing-a-directory-2641092
[Ruby]: https://www.thoughtco.com/what-is-ruby-2907828
[current directory]: https://ruby-doc.org/core-2.2.0/Dir.html
[case sensitivity]: https://www.tutorialspoint.com/ruby/ruby_syntax.htm
[Linux]: https://www.thoughtco.com/instal-ruby-on-linux-2908370
[https_www.thoughtco.com_using-glob-with-directories-2907832]: https://www.thoughtco.com/using-glob-with-directories-2907832