YAML

Collection Indicators

?

Key indicator

:

Value indicator

-

Nested series entry indicator

,

Separate in-line branch entries

[]

Surround in-line series branch

{}

Surround in-line keyed branch

Scalar Indicators

''

Surround in-line unescaped scalar ('' escaped ')

"

Surround in-line escaped scalar (see escape codes below)

|

Block scalar indicator

>

Folded scalar indicator

-

Strip chomp modifier (|- or >-)

+

Keep chomp modifier (|+ or >+)

1-9

Explicit indentation modifier (|1 or >2)

Modifiers can be combined (|2-, >+1)

Alias Indicators

&

Anchor property

*

Alias indicator

Tag Property (usually unspecified)

none

Unspecified tag (automatically resolved by application)

!

Non-specific tag (by default, !!map/!!seq/!!str)

!foo

Primary (by convention, means a local !foo tag)

!!foo

Secondary (by convention, means tag:yaml.org,2002:foo)

!h!foo

Requires %TAG !h! <prefix> (and then means <prefix>foo)

!<foo>

Verbatim tag (always means foo)

Document Indicators

%

Directive indicator

---

Document header

...

Document terminator

Misc Indicators

#

Throwaway comment indicator

`@

Both reserved for future use

Special Keys

=

Default "value" mapping key

<<

Merge keys from another mapping

Core Types (default automatic tags)

!!map

{ Hash table, dictionary, mapping }

!!seq

{ List, array, tuple, vector, sequence }

!!str

Unicode string

More Types

!!set

{ cherries, plums, apples }

!!omap

[ one: 1, two: 2 ]

Language Independent Scalar Types

{ ~, null }

Null (no value)

[ 1234, 0x4D2, 02333 ]

[ Decimal int, Hexadecimal int, Octal int ]

[ 1_230.15, 12.3015e+02 ]

[ Fixed float, Exponential float ]

[ .inf, -.Inf, .NAN ]

[ Infinity (float), Negative, Not a number ]

{ Y, true, Yes, ON }

Boolean true

{ n, FALSE, No, off }

Boolean false

 
? !!binary >
  R0lG...BADS=
 
>-
  Base 64 binary value

Escape Codes

Numeric

"\x12"       : 8-bit
"\u1234"     : 16-bit
"\U00102030" : 32-bit

Protective

"\\"     : '\'
"\""     : '"'
"\ "     : ' '
"\<TAB>" : TAB

C

"\0": NUL
"\a": BEL
"\b": BS
"\f": FF
"\n": LF
"\r": CR
"\t": TAB
"\v": VTAB

Additional

"\e": ESC
"\_": NBSP
"\N": NEL
"\L": LS
"\P": PS

Notes