GIT 和 YAML

其他答案都很好。先读这些。但是我还要加上另一个有时使用YAML的原因:git。

越来越多的编程项目使用git存储库进行分发和归档。而且，虽然git回购的历史记录可以同样存储JSON和YAML文件，但用于跟踪和显示文件更改的“diff”方法是面向行的。由于YAML被迫面向行，因此YAML文件中的任何小更改都更容易被人看到。

当然，JSON文件确实可以通过对字符串/键进行排序和添加缩进来“变得漂亮”。但这不是默认的，我很懒。

就我个人而言，我通常使用JSON进行系统到系统的交互。我经常将YAML用于配置文件、静态文件和跟踪文件。(我通常也避免添加YAML关系锚。生命太短暂，没有时间去寻找循环。)

此外，如果速度和空间真的是一个问题，我都不用。你可能想看看BSON。

基准测试结果

下面是在Python和Perl上比较YAML和JSON加载时间的基准测试结果

JSON要快得多，但牺牲了一些可读性和注释等特性

测试方法

在一台快速机器上连续运行100次，平均秒数 数据集是一个3.44MB的JSON文件，包含从维基百科抓取的电影数据 https://raw.githubusercontent.com/prust/wikipedia-movie-data/master/movies.json 链接来源:https://github.com/jdorfman/awesome-json-datasets

结果

Python 3.8.3 timeit
    JSON:            0.108
    YAML CLoader:    3.684
    YAML:           29.763

Perl 5.26.2 Benchmark::cmpthese
    JSON XS:         0.107
    YAML XS:         0.574
    YAML Syck:       1.050

Perl 5.26.2 Dumbbench (Brian D Foy, excludes outliers)
    JSON XS:         0.102
    YAML XS:         0.514
    YAML Syck:       1.027

差异:

YAML, depending on how you use it, can be more readable than JSON JSON is often faster and is probably still interoperable with more systems It's possible to write a "good enough" JSON parser very quickly Duplicate keys, which are potentially valid JSON, are definitely invalid YAML. YAML has a ton of features, including comments and relational anchors. YAML syntax is accordingly quite complex, and can be hard to understand. It is possible to write recursive structures in yaml: {a: &b [*b]}, which will loop infinitely in some converters. Even with circular detection, a "yaml bomb" is still possible (see xml bomb). Because there are no references, it is impossible to serialize complex structures with object references in JSON. YAML serialization can therefore be more efficient. In some coding environments, the use of YAML can allow an attacker to execute arbitrary code.

观察:

Python programmers are generally big fans of YAML, because of the use of indentation, rather than bracketed syntax, to indicate levels. Many programmers consider the attachment of "meaning" to indentation a poor choice. If the data format will be leaving an application's environment, parsed within a UI, or sent in a messaging layer, JSON might be a better choice. YAML can be used, directly, for complex tasks like grammar definitions, and is often a better choice than inventing a new language.

有时候你不需要在两者之间做出选择。

例如，在围棋中，你可以同时拥有这两者:

type Person struct {
    Name string `json:"name" yaml:"name"`
    Age int `json:"age" yaml:"age"`
}

绕过深奥的理论

这回答了标题，而不是细节，因为大多数人只是从谷歌上的搜索结果中阅读标题，就像我一样，所以我觉得有必要从web开发人员的角度解释。

YAML uses space indentation, which is familiar territory for Python developers. JavaScript developers love JSON because it is a subset of JavaScript and can be directly interpreted and written inside JavaScript, along with using a shorthand way to declare JSON, requiring no double quotes in keys when using typical variable names without spaces. There are a plethora of parsers that work very well in all languages for both YAML and JSON. YAML's space format can be much easier to look at in many cases because the formatting requires a more human-readable approach. YAML's form while being more compact and easier to look at can be deceptively difficult to hand edit if you don't have space formatting visible in your editor. Tabs are not spaces so that further confuses if you don't have an editor to interpret your keystrokes into spaces. JSON is much faster to serialize and deserialize because of significantly less features than YAML to check for, which enables smaller and lighter code to process JSON. A common misconception is that YAML needs less punctuation and is more compact than JSON but this is completely false. Whitespace is invisible so it seems like there are less characters, but if you count the actual whitespace which is necessary to be there for YAML to be interpreted properly along with proper indentation, you will find YAML actually requires more characters than JSON. JSON doesn't use whitespace to represent hierarchy or grouping and can be easily flattened with unnecessary whitespace removed for more compact transport.

房间里的大象:互联网本身

JavaScript显然以巨大的优势统治着网络，JavaScript开发人员更喜欢使用JSON作为数据格式，以及流行的web api，因此在进行一般意义上的web编程时，很难争论使用YAML还是JSON，因为在团队环境中你可能会被压倒。事实上，大多数web程序员甚至不知道YAML的存在，更不用说考虑使用它了。

如果你正在做任何web编程，JSON是默认的方式，因为使用JavaScript时不需要翻译步骤，所以在这种情况下，你必须提出一个更好的参数来使用YAML而不是JSON。

由于这个问题现在在搜索YAML和JSON时非常突出，值得注意的是两者之间一个很少被引用的区别:许可证。JSON声称拥有一个JSON用户必须遵守的许可(包括法律上模棱两可的“应使用代表善，而不是恶”)。YAML没有这样的许可声明，这可能是一个重要的区别(对您的律师来说，如果不是对您来说)。