YAML's syntax is similar to other high-level languages, and can easily express data forms such as lists, hash tables, and scalars. It uses whitespace indentation and a lot of appearance-dependent features, especially suitable for expressing or editing data structures, various configuration files, dumping debugging content, file outlines (for example: many email header formats are very close to YAML). Although it is more suitable for expressing hierarchical model data structures, there is also a refined syntax for representing relational model data. Because YAML uses blank characters and line breaks to separate data, it is especially suitable for grep/Python/Perl/Ruby operations. Its most easy-to-use feature is to skillfully avoid all kinds of closed symbols, such as: quotation marks, various brackets, etc. These symbols will become complicated and difficult to recognize when nesting structures.