Ansible merge list - list

Question

I have two lists as below, List1 and List2. Field a is common in two lists. I need to merge and create a new list.
For an example, I have created 3 fields(like a,b,c), it may have 8 -10 fields.
List1:
[{"a" : "1",
"b": "2",
"c" : "3"
},
{"a" : "5",
"b": "6",
"c" : "7"
},
{"a" : "8",
"b": "9",
"c" : "10"
},
{"a" : "11",
"b": "12",
"c" : "13"
},
{"a" : "20",
"b": "212",
"c" : "213"
}
]
List2:
[{"a" : "1",
"d": "22",
"e" : "32"
},
{"a" : "5",
"d": "62",
"e" : "72"
},
{"a" : "8",
"d": "92",
"e" : "210"
},
{"a" : "11",
"d": "1222",
"e" : "1322"
}
]
New list:
[{"a" : "1",
"b": "2",
"c" : "3",
"d": "22",
"e" : "32"
},
{"a" : "5",
"b": "6",
"c" : "7",
"d": "62",
"e" : "72"
},
{"a" : "8",
"b": "9",
"c" : "10",
"d": "92",
"e" : "210"
},
{"a" : "11",
"b": "12",
"c" : "13",
"d": "1222",
"e" : "1322"
}
]

Answer 1

Update.
Recent filter combine can be applied to the lists of dictionaries. Given the lists
list1:
- {a: '1', b: '2', c: '3'}
- {a: '5', b: '6', c: '7'}
- {a: '8', b: '9', c: '10'}
- {a: '11', b: '12', c: '13'}
- {a: '20', b: '212', c: '213'}
list2:
- {a: '1', d: '22', e: '32'}
- {a: '5', d: '62', e: '72'}
- {a: '8', d: '92', e: '210'}
- {a: '11', d: '1222', e: '1322'}
Declare the list3
list3: "{{ list1|zip(list2)|map('combine')|list }}"
gives the expected result
list3:
- {a: '1', b: '2', c: '3', d: '22', e: '32'}
- {a: '5', b: '6', c: '7', d: '62', e: '72'}
- {a: '8', b: '9', c: '10', d: '92', e: '210'}
- {a: '11', b: '12', c: '13', d: '1222', e: '1322'}
Example of a complete playbook for testing
- hosts: localhost
vars:
list1:
- {a: '1', b: '2', c: '3'}
- {a: '5', b: '6', c: '7'}
- {a: '8', b: '9', c: '10'}
- {a: '11', b: '12', c: '13'}
- {a: '20', b: '212', c: '213'}
list2:
- {a: '1', d: '22', e: '32'}
- {a: '5', d: '62', e: '72'}
- {a: '8', d: '92', e: '210'}
- {a: '11', d: '1222', e: '1322'}
list3: "{{ list1|zip(list2)|map('combine')|list }}"
tasks:
- debug:
var: list1|to_yaml
- debug:
var: list2|to_yaml
- debug:
var: list3|to_yaml
Original.
The task below does the job
- set_fact:
list3: "{{ list3|default([]) + [item.0|combine(item.1)] }}"
loop: "{{ list1|zip(list2)|list }}"
- debug:
var: list3
gives
list3:
- a: '1'
b: '2'
c: '3'
d: '22'
e: '32'
- a: '5'
b: '6'
c: '7'
d: '62'
e: '72'
- a: '8'
b: '9'
c: '10'
d: '92'
e: '210'
- a: '11'
b: '12'
c: '13'
d: '1222'
e: '1322'
Optionally sort the lists
loop: "{{ list1|sort(attribute='a')|
zip(list2|sort(attribute='a'))|list }}"
and test the attribute 'a'
- fail:
msg: "[ERROR] Items a do no match."
loop: "{{ list1|sort(attribute='a')|
zip(list2|sort(attribute='a'))|list }}"
when: item.0.a != item.1.a