In YAML, you can easily create multi-line strings. However, I would like the ability to create a multi-line array (mainly for readibility within config files) using the | character.
A YAML array can be represented as: ['key1', 'key2', 'key3'].
A YAML sequence uses a dash followed by a space and then a string:
- String1
- String2
- String3
This would evaluate to: ['string1', 'string2', 'string3'].
A YAML mapping is an array of key and value pairs that we see all the time in YAML:
Key1: string1
Key2: string2
Key3: string3
This is all well and good, but I can't for the life of me see how to do a multi-line array. Something like this:
|
['string1', 'string2', 'string3']
['string4', 'string5', 'string6']
Short of creating multiple array mappings in YAML and merging them in my programming language of choice, is there any way to achieve multi-line arrays, maybe with { } like Python has but in YAML?
5 Answers
A YAML sequence is an array. So this is the right way to express it:
key:
- string1
- string2
- string3
- string4
- string5
- string6
That's identical in meaning to:
key: ['string1', 'string2', 'string3', 'string4', 'string5', 'string6']
It's also legal to split a single-line array over several lines:
key: ['string1', 'string2', 'string3',
'string4', 'string5',
'string6']
and even have multi-line strings in single-line arrays:
key: ['string1', 'long
string', 'string3', 'string4', 'string5', 'string6']
have you tried this?
-
name: Jack
age: 32
-
name: Claudia
age: 25
I get this: [{"name"=>"Jack", "age"=>32}, {"name"=>"Claudia", "age"=>25}] (I use the YAML Ruby class).
If what you are needing is an array of arrays, you can do this way:
key:
- [ 'value11', 'value12', 'value13' ]
- [ 'value21', 'value22', 'value23' ]
The following would work:
myarray: [
String1, String2, String3,
String4, String5, String5, String7
]
I tested it using the snakeyaml implementation, I am not sure about other implementations though.
The following works for me and its good from readability point of view when the number of array element values is small:
key: [string1, string2, string3, string4, string5, string6]
This has been tested to work with snakeyaml and ruamel.yaml.
