Metadata-Version: 2.1
Name: pydeepmerge
Version: 0.2.1b2
Summary: A lightweight library to perform deep merges of python dictionaries
Home-page: https://github.com/taliamax/pydeepmerge
Maintainer: Natalia Maximo
Maintainer-email: iam@natalia.dev
License: MIT
Platform: UNKNOWN
Classifier: Development Status :: 4 - Beta
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Requires-Python: >=3.5
Description-Content-Type: text/markdown

# DeepMerge

![build status](https://img.shields.io/github/workflow/status/taliamax/pydeepmerge/build) ![MIT license](https://img.shields.io/pypi/l/pydeepmerge) ![coverage status](https://img.shields.io/coveralls/github/taliamax/pydeepmerge) 

![pypi version](https://img.shields.io/pypi/v/pydeepmerge) ![pypi python versions supported](https://img.shields.io/pypi/pyversions/pydeepmerge) ![pypi downloads](https://img.shields.io/pypi/dm/pydeepmerge)

A lightweight python package for performing deep-merges of python dictionaries

Usage is simple:

```python
from pydeepmerge import deep_merge

> some_data = {'foo': {'bar': 'baz', 'spam': 'eggs'}, 'ham': 'eggs'}
> more_data = {'spam': {'eggs': 'ham'}, 'foo': {'baz': 'bar', 'bar': 'foo'}}
> deep_merge(some_data, more_data)
{'foo': {'bar': 'foo', 'baz': 'bar', 'spam': 'eggs'}, 'spam': {'eggs': 'ham'}, 'ham': 'eggs'}
```

`pydeepmerge` also allows users to specify their own merge strategy function. By default, it uses the function `prefer_right`.

A merge strategy is any function that can accept exactly two inputs. The output of the merge strategy function should be what the merge result between two values should be.

When writing your own merge strategy function, keep in mind that if the key does not exist on the left-hand mapping, the value `Key.NoKeyFound` will be passed to the first parameter of the function. This is done deliberately so the user can determine if they want to do special behaviour if it is the first occurrence of the key in the sequence of dictionaries.

An example of a merge strategy function can be found below:

```python
from pydeepmerge import deep_merge
from pydeepmerge.types import Key
from typing import Mapping

def pick_shallower(left_value, right_value):
    if left_value is Key.NoKeyFound:
        return right_value

    if isinstance(right_value, Mapping):
        if not isinstance(left_value, Mapping):
            return left_value
        return deep_merge(left_value, right_value)

    return right_value
```

The `deep_merge` function does not mutate any mapping but instead creates a new dictionary.

