YAML cheatsheet Syntax
- yaml file or document:
yaml document contains multiple lines of text with the following rules.
At a high level, yaml documents are interpreted as Map or dictionaries
- The first line begins with
--- - End of the document with
... - each line of text contains key and value pairs like a
map. - key and values are separated by a colon (
:) and space - use spaces instead of the tab for indentation
a simple key and value mapping
key: value
a simple key and complex value mapping
key:< key2
key3: value1 < value
Key accepts strings value can be one of the following
- Scalar types
- sequence or collection type
- nested collections
yaml indent/spaces
tab spaces (4 spaces) are not allowed and give an error
There are two types of syntaxes
- Indented blocks
- Inline blocks
Indented blocks syntax
Inline blocks use indentation or spaces for each line the new line is introduced to create a key and values
id: 1
name: Franc
salary: 5000
Inline blocks syntax
all the keys and value pairs are separated by a comma and declared in braces, value is separated by colon and spaces
{id:1,name: Franc,salary: 5000}
yaml datatypes
The following data types are supported by YAML:
| Types | Description |
|---|---|
| String | Strings are enclosed with or without double or single quotes |
| number | It can be integers or floating values |
| Boolean | Accepts true or false |
| sequence | Supports array or list |
| Set | Set stores the elements unordered without duplicates |
| Map | maps stores key with value as like hash map |
| binary | support binary data of octal strings - images, files |
| timestamp | Supports date, DateTime |
Scalars types - number, boolean, strings
Scalars are of integers or floating values, strings, Boolean values Strings can be enclosed in single double or unquoted
value:11
pivalue:3.14
isEnabled:false
strvalue1:'string value1'
strvalue2:"string value2"
strvalue3: string value3
Collection types
The following collections are supported
- Sequence
- Set
- Nested Map or Dictionary
Sequence type
Sequences are like arrays or lists. Please see Sequence
Set
A Set is a list of unordered elements. It does not preserve duplicate elements.
Set stores the elements with null values
There are two types of syntax representation
typed sets
using specifying !!set tag and ? symbol makes the set
numbers:!! set
? one
? two
? three
flow style sets
It is json representation of values using !!set
numbers: !!set { 'one', "two", three }
the equivalent of the above two set examples a map
numbers:
one: null
two: null
three: null
Dictionary or Nested Map
each line of the document and key and value pairs Each value can be nested with other documents using indentation. Using 2 spaces is a prerequisite, tabs are not supported
Employee:
id: 1
name: "Franc"
department:
name: "Sales"
depid: "11"
