2.5 KiB
Add behaves differently according to the type of the LHS:
- arrays: concatenate
- number scalars: arithmetic addition
- string scalars: concatenate
Use += as append assign for things like increment. Note that .a += .x is equivalent to running .a = .a + .x.
Concatenate and assign arrays
Given a sample.yml file of:
a:
val: thing
b:
- cat
- dog
then
yq eval '.a.b += ["cow"]' sample.yml
will output
a:
val: thing
b:
- cat
- dog
- cow
Concatenate arrays
Given a sample.yml file of:
a:
- 1
- 2
b:
- 3
- 4
then
yq eval '.a + .b' sample.yml
will output
- 1
- 2
- 3
- 4
Concatenate null to array
Given a sample.yml file of:
a:
- 1
- 2
then
yq eval '.a + null' sample.yml
will output
- 1
- 2
Add new object to array
Given a sample.yml file of:
a:
- dog: woof
then
yq eval '.a + {"cat": "meow"}' sample.yml
will output
- dog: woof
- cat: meow
Add string to array
Given a sample.yml file of:
a:
- 1
- 2
then
yq eval '.a + "hello"' sample.yml
will output
- 1
- 2
- hello
Update array (append)
Given a sample.yml file of:
a:
- 1
- 2
b:
- 3
- 4
then
yq eval '.a = .a + .b' sample.yml
will output
a:
- 1
- 2
- 3
- 4
b:
- 3
- 4
String concatenation
Given a sample.yml file of:
a: cat
b: meow
then
yq eval '.a = .a + .b' sample.yml
will output
a: catmeow
b: meow
Relative string concatenation
Given a sample.yml file of:
a: cat
b: meow
then
yq eval '.a += .b' sample.yml
will output
a: catmeow
b: meow
Number addition - 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: 4.9
then
yq eval '.a = .a + .b' sample.yml
will output
a: 7.9
b: 4.9
Number addition - 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 eval '.a = .a + .b' sample.yml
will output
a: 7
b: 4
Increment number
Given a sample.yml file of:
a: 3
then
yq eval '.a += 1' sample.yml
will output
a: 4
Add to null
Adding to null simply returns the rhs
Running
yq eval --null-input 'null + "cat"'
will output
cat