YAML dictionaries, also known as mappings or associative arrays, are fundamental structures in YAML for representing key-value pairs. They provide an intuitive way to organize and store data in a hierarchical format.

Basic Syntax

In YAML, dictionaries are defined using a colon (:) to separate keys from values. Each key-value pair is typically written on a new line, with the key followed by a colon and the value.


key1: value1
key2: value2
key3: value3

Inline Dictionaries

For compact representation, YAML allows inline dictionary notation using curly braces {}:


{key1: value1, key2: value2, key3: value3}

Complex Values

Dictionary values can be of various types, including strings, numbers, booleans, lists, or even nested dictionaries.


person:
  name: John Doe
  age: 30
  is_employee: true
  hobbies:
    - reading
    - swimming
  address:
    street: 123 Main St
    city: Anytown

Key Considerations

Keys must be unique within a dictionary
Keys are case-sensitive
Indentation is crucial for nested structures
Use quotes for keys or values containing special characters

Common Use Cases

YAML dictionaries are widely used in various applications, including:

Configuration files
Data serialization
API responses
Structured data storage

Advanced Features

YAML offers advanced features for working with dictionaries, such as YAML Anchors and YAML Aliases for reusing content, and YAML Merge Keys for combining dictionaries.

Best Practices

Use meaningful key names for clarity
Maintain consistent indentation (typically 2 or 4 spaces)
Avoid overly complex nested structures
Consider using YAML Comments for documentation

By mastering YAML dictionaries, you'll be able to create well-structured, readable data representations for various applications, from simple configurations to complex data models.