mirror of
https://github.com/adambard/learnxinyminutes-docs.git
synced 2024-12-26 18:58:51 +00:00
140 lines
4.1 KiB
Markdown
140 lines
4.1 KiB
Markdown
---
|
|
language: yaml
|
|
filename: learnyaml.yaml
|
|
contributors:
|
|
- ["Adam Brenecki", "https://github.com/adambrenecki"]
|
|
---
|
|
|
|
YAML is a data serialisation language designed to be directly writable and
|
|
readable by humans.
|
|
|
|
It's a strict superset of JSON, with the addition of syntactically
|
|
significant newlines and indentation, like Python. Unlike Python, however,
|
|
YAML doesn't allow literal tab characters at all.
|
|
|
|
```yaml
|
|
# Comments in YAML look like this.
|
|
|
|
################
|
|
# SCALAR TYPES #
|
|
################
|
|
|
|
# Our root object (which continues for the entire document) will be a map,
|
|
# which is equivalent to a dictionary, hash or object in other languages.
|
|
key: value
|
|
another_key: Another value goes here.
|
|
a_number_value: 100
|
|
scientific_notation: 1e+12
|
|
boolean: true
|
|
null_value: null
|
|
key with spaces: value
|
|
# Notice that strings don't need to be quoted. However, they can be.
|
|
however: "A string, enclosed in quotes."
|
|
"Keys can be quoted too.": "Useful if you want to put a ':' in your key."
|
|
|
|
# Multiple-line strings can be written either as a 'literal block' (using |),
|
|
# or a 'folded block' (using '>').
|
|
literal_block: |
|
|
This entire block of text will be the value of the 'literal_block' key,
|
|
with line breaks being preserved.
|
|
|
|
The literal continues until de-dented, and the leading indentation is
|
|
stripped.
|
|
|
|
Any lines that are 'more-indented' keep the rest of their indentation -
|
|
these lines will be indented by 4 spaces.
|
|
folded_style: >
|
|
This entire block of text will be the value of 'folded_style', but this
|
|
time, all newlines will be replaced with a single space.
|
|
|
|
Blank lines, like above, are converted to a newline character.
|
|
|
|
'More-indented' lines keep their newlines, too -
|
|
this text will appear over two lines.
|
|
|
|
####################
|
|
# COLLECTION TYPES #
|
|
####################
|
|
|
|
# Nesting is achieved by indentation.
|
|
a_nested_map:
|
|
key: value
|
|
another_key: Another Value
|
|
another_nested_map:
|
|
hello: hello
|
|
|
|
# Maps don't have to have string keys.
|
|
0.25: a float key
|
|
|
|
# Keys can also be multi-line objects, using ? to indicate the start of a key.
|
|
? |
|
|
This is a key
|
|
that has multiple lines
|
|
: and this is its value
|
|
|
|
# YAML also allows collection types in keys, but many programming languages
|
|
# will complain.
|
|
|
|
# Sequences (equivalent to lists or arrays) look like this:
|
|
a_sequence:
|
|
- Item 1
|
|
- Item 2
|
|
- 0.5 # sequences can contain disparate types.
|
|
- Item 4
|
|
- key: value
|
|
another_key: another_value
|
|
-
|
|
- This is a sequence
|
|
- inside another sequence
|
|
|
|
# Since YAML is a superset of JSON, you can also write JSON-style maps and
|
|
# sequences:
|
|
json_map: {"key": "value"}
|
|
json_seq: [3, 2, 1, "takeoff"]
|
|
|
|
#######################
|
|
# EXTRA YAML FEATURES #
|
|
#######################
|
|
|
|
# YAML also has a handy feature called 'anchors', which let you easily duplicate
|
|
# content across your document. Both of these keys will have the same value:
|
|
anchored_content: &anchor_name This string will appear as the value of two keys.
|
|
other_anchor: *anchor_name
|
|
|
|
# YAML also has tags, which you can use to explicitly declare types.
|
|
explicit_string: !!str 0.5
|
|
# Some parsers implement language specific tags, like this one for Python's
|
|
# complex number type.
|
|
python_complex_number: !!python/complex 1+2j
|
|
|
|
####################
|
|
# EXTRA YAML TYPES #
|
|
####################
|
|
|
|
# Strings and numbers aren't the only scalars that YAML can understand.
|
|
# ISO-formatted date and datetime literals are also parsed.
|
|
datetime: 2001-12-15T02:59:43.1Z
|
|
datetime_with_spaces: 2001-12-14 21:59:43.10 -5
|
|
date: 2002-12-14
|
|
|
|
# The !!binary tag indicates that a string is actually a base64-encoded
|
|
# representation of a binary blob.
|
|
gif_file: !!binary |
|
|
R0lGODlhDAAMAIQAAP//9/X17unp5WZmZgAAAOfn515eXvPz7Y6OjuDg4J+fn5
|
|
OTk6enp56enmlpaWNjY6Ojo4SEhP/++f/++f/++f/++f/++f/++f/++f/++f/+
|
|
+f/++f/++f/++f/++f/++SH+Dk1hZGUgd2l0aCBHSU1QACwAAAAADAAMAAAFLC
|
|
AgjoEwnuNAFOhpEMTRiggcz4BNJHrv/zCFcLiwMWYNG84BwwEeECcgggoBADs=
|
|
|
|
# YAML also has a set type, which looks like this:
|
|
set:
|
|
? item1
|
|
? item2
|
|
? item3
|
|
|
|
# Like Python, sets are just maps with null values; the above is equivalent to:
|
|
set2:
|
|
item1: null
|
|
item2: null
|
|
item3: null
|
|
```
|