mergedeep

A deep merge function for 🐍.

Check out the mergedeep docs

Installation

$ pip install mergedeep

Usage

merge(target: Map[KT, VT], *sources: Map[KT, VT], strategy: Strategy = Strategy.REPLACE) -> Map[KT, VT]

Deep merge without mutating the source dicts.

from mergedeep import merge

a = {"keyA": 1}
b = {"keyB": {"sub1": 10}}
c = {"keyB": {"sub2": 20}}

merged = merge({}, a, b, c) 

print(merged)
# {"keyA": 1, "keyB": {"sub1": 10, "sub2": 20}}

Deep merge into an existing dict.

from mergedeep import merge

a = {"keyA": 1}
b = {"keyB": {"sub1": 10}}
c = {"keyB": {"sub2": 20}}

merge(a, b, c) 

print(a)
# {"keyA": 1, "keyB": {"sub1": 10, "sub2": 20}}

Merge strategies:

1. Replace (default)

# Strategy.REPLACE
# When `target` and `source` values are the same, replace the `target` value with one from `source` (default).
# Note: with multiple sources, the `last` source value will be what appears in the merged result. 

from mergedeep import merge, Strategy

target = {"key": [1, 2]}
source = {"key": [3, 4]}

merge(target, source, strategy=Strategy.REPLACE) 
# same as: merge(target, source)

print(target)
# {"key": [3, 4]}

2. Additive

# Strategy.ADDITIVE
# When `target` and `source` values are both either `list`, `tuple`, or `set`, extend/update `target` with values from `source` collection.

from mergedeep import merge, Strategy

target = {"key": [1, 2]}
source = {"key": [3, 4]}

merge(target, source, strategy=Strategy.ADDITIVE) 

print(target)
# {"key": [1, 2, 3, 4]}

3. Typesafe replace

# Strategy.TYPESAFE_REPLACE or Strategy.TYPESAFE 
# When `target` and `source` values are of different types, raise `TypeError`. Otherwise, perform a `REPLACE` merge.

from mergedeep import merge, Strategy

target = {"key": [1, 2]}
source = {"key": {3, 4}}

merge(target, source, strategy=Strategy.TYPESAFE_REPLACE) # or `Strategy.TYPESAFE`  
# TypeError: target type: <class 'list'> differs from source type: <class 'set'> for key: "key"

4. Typesafe additive

# Strategy.TYPESAFE_ADDITIVE
# When `target` and `source` values are of different types, raise `TypeError`. Otherwise, perform a `ADDITIVE` merge.

from mergedeep import merge, Strategy

target = {"key": [1, 2]}
source = {"key": {3, 4}}

merge(target, source, strategy=Strategy.TYPESAFE_ADDITIVE) 
# TypeError: target type: <class 'list'> differs from source type: <class 'set'> for key: "key"

License

MIT © Travis Clarke