What is YAML?
YAML (YAML Ain't Markup Language) is a human-readable data format used for configuration files, automation scripts, and data exchange.
Basic Concepts of YAML
Key-Value Pairs
YAML stores data as key-value pairs, similar to JSON or dictionaries.
Example:
name: John Doe
age: 30
city: Bangkok
Keys: name, age, city
Values: "John Doe", 30, "Bangkok"
Indentation Instead of Braces
YAML uses spaces for indentation instead of {} or [].
Example:
person:
name: John Doe
age: 30
address:
city: Bangkok
country: Thailand
Use spaces, NOT tabs!
Lists (Arrays)
Lists are created using dashes (-).
Example:
fruits:
- Apple
- Banana
- Mango
Equivalent in JSON:
{ "fruits": ["Apple", "Banana", "Mango"] }
Lists can also contain objects:
employees:
- name: Alice
age: 28
- name: Bob
age: 35
Data Types
YAML supports various data types:
string_value: "Hello, YAML!"
integer_value: 25
float_value: 99.9
boolean_value: true
null_value: null
Multi-line Strings
Use | for preserved formatting:
description: |
This is a multi-line text.
The formatting is preserved.
Use > for folded (single-line) text:
summary: >
This is a multi-line text.
But it will be converted into a single line.
Equivalent: "This is a multi-line text. But it will be converted into a single line."
Comments
Use # for comments:
#This is a comment
app_name: MyApp # Inline comment
