fa6fac1a76
* Remove extra backtick * Reword explanation of update * Reword explanation of relative update * Change "remaple" to "remain" * Change "clovver" to "clobber" * Reword explanation of update for comment operators * Reword explanation of relative update for comment operators * Change "array" to "expression" * Change "the golangs" to "Golang's" * Change "golangs" to "Golang's" * Change "can durations" to "can add durations" * Change "array scalars" to "arrays" * Change "beit" to "be it" * Fix typo in `eval` tip * Fix typo in header for `has` operation * Add space before pipe in `line` operator example * Fix typos in explanation of deep array merges * Change "is now used" to "is now used." * Change "object," to "object." * Changes "indexes" to "indices" * Remove extraneous copied text from `..` article * Reword explanation of `...` operator * Change "your are" to "you are" * Add link to `string` operator docs in `select` article * Change "is a" to "parameter specifies" in `string` operators article * Change "new line" to "newline" * Change "golang regex" to "Golang's regex" * Change "golang" to "Golang" * Add period * Remove comma in `subtract` article * Remove duplicate number subtraction example * Remove comma in `traverse` operator article * Clarify use of brackets when `read`ing with special characters
4.1 KiB
Anchor and Alias Operators
Use the alias and anchor operators to read and write yaml aliases and anchors. The explode operator normalises a yaml file (dereference (or expands) aliases and remove anchor names).
yq supports merge aliases (like <<: *blah) however this is no longer in the standard yaml spec (1.2) and so yq will automatically add the !!merge tag to these nodes as it is effectively a custom tag.
Merge one map
see https://yaml.org/type/merge.html
Given a sample.yml file of:
- &CENTER
x: 1
y: 2
- &LEFT
x: 0
y: 2
- &BIG
r: 10
- &SMALL
r: 1
- !!merge <<: *CENTER
r: 10
then
yq '.[4] | explode(.)' sample.yml
will output
x: 1
y: 2
r: 10
Merge multiple maps
see https://yaml.org/type/merge.html
Given a sample.yml file of:
- &CENTER
x: 1
y: 2
- &LEFT
x: 0
y: 2
- &BIG
r: 10
- &SMALL
r: 1
- !!merge <<:
- *CENTER
- *BIG
then
yq '.[4] | explode(.)' sample.yml
will output
r: 10
x: 1
y: 2
Override
see https://yaml.org/type/merge.html
Given a sample.yml file of:
- &CENTER
x: 1
y: 2
- &LEFT
x: 0
y: 2
- &BIG
r: 10
- &SMALL
r: 1
- !!merge <<:
- *BIG
- *LEFT
- *SMALL
x: 1
then
yq '.[4] | explode(.)' sample.yml
will output
r: 10
x: 1
y: 2
Get anchor
Given a sample.yml file of:
a: &billyBob cat
then
yq '.a | anchor' sample.yml
will output
billyBob
Set anchor
Given a sample.yml file of:
a: cat
then
yq '.a anchor = "foobar"' sample.yml
will output
a: &foobar cat
Set anchor relatively using assign-update
Given a sample.yml file of:
a:
b: cat
then
yq '.a anchor |= .b' sample.yml
will output
a: &cat
b: cat
Get alias
Given a sample.yml file of:
b: &billyBob meow
a: *billyBob
then
yq '.a | alias' sample.yml
will output
billyBob
Set alias
Given a sample.yml file of:
b: &meow purr
a: cat
then
yq '.a alias = "meow"' sample.yml
will output
b: &meow purr
a: *meow
Set alias to blank does nothing
Given a sample.yml file of:
b: &meow purr
a: cat
then
yq '.a alias = ""' sample.yml
will output
b: &meow purr
a: cat
Set alias relatively using assign-update
Given a sample.yml file of:
b: &meow purr
a:
f: meow
then
yq '.a alias |= .f' sample.yml
will output
b: &meow purr
a: *meow
Explode alias and anchor
Given a sample.yml file of:
f:
a: &a cat
b: *a
then
yq 'explode(.f)' sample.yml
will output
f:
a: cat
b: cat
Explode with no aliases or anchors
Given a sample.yml file of:
a: mike
then
yq 'explode(.a)' sample.yml
will output
a: mike
Explode with alias keys
Given a sample.yml file of:
f:
a: &a cat
*a: b
then
yq 'explode(.f)' sample.yml
will output
f:
a: cat
cat: b
Explode with merge anchors
Given a sample.yml file of:
foo: &foo
a: foo_a
thing: foo_thing
c: foo_c
bar: &bar
b: bar_b
thing: bar_thing
c: bar_c
foobarList:
b: foobarList_b
!!merge <<:
- *foo
- *bar
c: foobarList_c
foobar:
c: foobar_c
!!merge <<: *foo
thing: foobar_thing
then
yq 'explode(.)' sample.yml
will output
foo:
a: foo_a
thing: foo_thing
c: foo_c
bar:
b: bar_b
thing: bar_thing
c: bar_c
foobarList:
b: bar_b
thing: foo_thing
c: foobarList_c
a: foo_a
foobar:
c: foo_c
a: foo_a
thing: foobar_thing
Dereference and update a field
Use explode with multiply to dereference an object
Given a sample.yml file of:
item_value: &item_value
value: true
thingOne:
name: item_1
!!merge <<: *item_value
thingTwo:
name: item_2
!!merge <<: *item_value
then
yq '.thingOne |= explode(.) * {"value": false}' sample.yml
will output
item_value: &item_value
value: true
thingOne:
name: item_1
value: false
thingTwo:
name: item_2
!!merge <<: *item_value