Subtract

You can use subtract to subtract numbers as well as remove elements from an array.
Array subtraction
Running
yq --null-input '[1,2] - [2,3]'
will output
- 1
Array subtraction with nested array
Running
yq --null-input '[[1], 1, 2] - [[1], 3]'
will output
- 1
- 2
Array subtraction with nested object
Note that order of the keys does not matter
Given a sample.yml file of:
- a: b
  c: d
- a: b
then
yq '. - [{"c": "d", "a": "b"}]' sample.yml
will output
- a: b
Number subtraction - float
If the lhs or rhs are floats then the expression will be calculated with floats.
Given a sample.yml file of:
a: 3
b: 4.5
then
yq '.a = .a - .b' sample.yml
will output
a: -1.5
b: 4.5
Number subtraction - int
If both the lhs and rhs are ints then the expression will be calculated with ints.
Given a sample.yml file of:
a: 3
b: 4
then
yq '.a = .a - .b' sample.yml
will output
a: -1
b: 4
Decrement numbers
Given a sample.yml file of:
a: 3
b: 5
then
yq '.[] -= 1' sample.yml
will output
a: 2
b: 4
Date subtraction
You can subtract durations from dates. Assumes RFC3339 date time format, see date-time operators for more information.
Given a sample.yml file of:
a: 2021-01-01T03:10:00Z
then
yq '.a -= "3h10m"' sample.yml
will output
a: 2021-01-01T00:00:00Z
Date subtraction - custom format
Use with_dtf to specify your datetime format. See date-time operators for more information.
Given a sample.yml file of:
a: Saturday, 15-Dec-01 at 6:00AM GMT
then
yq 'with_dtf("Monday, 02-Jan-06 at 3:04PM MST", .a -= "3h1m")' sample.yml
will output
a: Saturday, 15-Dec-01 at 2:59AM GMT
Custom types: that are really numbers
When custom tags are encountered, yq will try to decode the underlying type.
Given a sample.yml file of:
a: !horse 2
b: !goat 1
then
yq '.a -= .b' sample.yml
will output
a: !horse 1
b: !goat 1

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Last modified 6mo ago