Transform

Transformation utilities.

These functions are used to transform the data sent by Andesite into the Python models.

These functions aren’t exported to the andesite namespace, if you want to use them you need to import them from andesite.transform. However, there shouldn’t be a need for you to use them in the first place as andesite.py already does this for you.

RawDataType

(Type alias) JSON-like object data type.

Type

Dict[str, Any]

CONVERTER_MEMO

Memory used for letter case conversion.

Type

lettercase.ConversionMemo

MapFunction

(Type alias) Callable that takes an argument and returns a new one.

Type

20. -> Any

transform_input(cls, data)

Call the __transform_input__ classmethod on a model.

This is different from calling the method directly because it always returns the current data.

Parameters

• cls (Any) – Target model whose transformation to apply

• data (Dict[str, Any]) – Data to be transformed

The transform method can either manipulate the provided data or replace it entirely by returning something other than None.

Notes

When using this function inside of a transformation, make sure that you continue to work on the data returned by this function. Also, you cannot return None when using this function, you have to return the data. This is because you can’t be sure whether the data has been modified or replaced and modifications on a replaced value wouldn’t propagate upward unless you return them.

Return type

Dict[str, Any]

transform_output(cls, data)

Call the __transform_output__ classmethod on a model.

This is different from calling the method directly because it always returns the current data.

Parameters

• cls (Any) – Target model whose transformation to apply

• data (Dict[str, Any]) – Data to be transformed

The transform method can either manipulate the provided data or replace it entirely by returning something other than None.

Notes

When using this function inside of a transformation, make sure that you continue to work on the data returned by this function. Also, you cannot return None when using this function, you have to return the data. This is because you can’t be sure whether the data has been modified or replaced and modifications on a replaced value wouldn’t propagate upward unless you return them.

Return type

Dict[str, Any]

convert_to_raw(obj)

Convert a dataclass to a dict.

This behaves similar to dataclasses.asdict. The difference is outlined below.

The function uses transform_output, if the model provides a __transform_output__ method it will be called.

After transformation the keys of the data dict are converted from snake_case to dromedaryCase.

This does not copy the values of the dataclass, modifying a value of the resulting dict will also modify the dataclass’ value.

Parameters

obj (Any) – Object to convert to its raw representation. Usually this is a dataclass, however, you can also parse list, tuple, and dict objects which will convert its members. All other types will be returned without modifying them.

Return type

Dict[str, Any]

build_from_raw(cls, raw_data)

Build an instance of cls from the passed raw data.

In the spirit of the other transform functions, None is treated as a special value and returned directly instead of handling it in any way.

The function uses transform_input, if the model provides a __transform_input__ method it will be called.

After transformation the data is used as the keyword arguments to the cls constructor.

Parameters

• cls (Type[~T]) – Target type to build

• raw_data (Optional[Dict[str, Any]]) – Data which should be used to build the instance. If this is None, None is returned.

Return type

Optional[~T]

seq_build_all_items_from_raw(items, cls)

Build all items of a mutable sequence.

This calls build_from_raw on all items in the sequence and assigns the result to the index.

Parameters

• items (MutableSequence[Dict[str, Any]]) – Mutable sequence of raw data to be converted

• cls (Type[~T]) – Target type to build.

Return type

None

Returns

This method mutates the provided sequence, it does not return anything.

map_convert_value(mapping, key, func)

Call a function on the value of a key of the provided mapping.

The return value of the function then replaces the old value.

If the key does not exist in the mapping, it is ignored and the function is not called.

Parameters

• mapping (MutableMapping[~KT, ~T]) – Mutable mapping which is to be manipulated.

• key (~KT) – Key whose value in the mapping is to be converted. If this key does not exist in the mapping, the conversion is aborted and the function doesn’t perform any action.

• func (Callable[[~T], Any]) – Callback which will be called with the value of the key. Its return value then replaces the previous value in the mapping.

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

map_convert_values(mapping, **key_funcs)

Run a callback for a key.

For each key you can specify which function to run (<key> = <MapFunction>).

Parameters

• mapping (Dict[str, Any]) – Mutable mapping for which to apply the conversion

• **key_funcs – key -> map function mapping. For each key the specified function will be applied using map_convert_value.

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

map_convert_values_all(mapping, func, *keys)

Run the same callback on all keys.

Works like map_convert_values but runs the same function for all keys.

Parameters

• mapping (Dict[str, Any]) – Mutable mapping for which to apply the conversion

• func (Callable[[~T], Any]) – Function to apply to the values of the specified keys. The function is run using map_convert_value

• *keys – Keys whose values are to be converted.

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

map_build_values_from_raw(mapping, **key_types)

Build the values of the specified keys to the specified type.

Parameters

• mapping (Dict[str, Any]) – Mutable mapping for which to apply the conversion

• **key_types – key -> type mapping. For each key the value will be converted to the provided type using build_from_raw.

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

map_build_all_values_from_raw(mapping, cls)

Build all values of a mapping.

This calls build_from_raw on all values of the mapping and replaces the old value with the result.

Parameters

• mapping (MutableMapping[Any, Dict[str, Any]]) – Mutable mapping whose values are to be built

• cls (Type[~T]) – Type to convert the values to

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

from_milli(value)

Convert a number from thousandths to base.

Parameters

value (Optional[int]) – Value to convert from milli.

Returns

None if you pass None as the value, otherwise a float.

Return type

Optional[float]

to_milli(value)

Convert from base unit to thousandths.

Parameters

value (Optional[float]) – Value to convert to milli.

Returns

None if you pass None as the value, otherwise an int.

Return type

Optional[int]

from_centi(value)

Convert a number from hundredths to base.

Parameters

value (Optional[int]) – Value to convert from centi.

Returns

None if you pass None as the value, otherwise a float.

Return type

Optional[float]

to_centi(value)

Convert from base unit to hundredths.

This is really just multiplying by 1000.

Parameters

value (Optional[float]) – Value to convert to milli.

Returns

None if you pass None as the value, otherwise an int.

Return type

Optional[int]

map_convert_values_from_milli(mapping, *keys)

Run from_milli on all specified keys’ values.

Parameters

• mapping (Dict[str, Any]) – Mutable mapping for which to apply the conversion

• *keys – Keys whose values to convert from milli. Uses from_milli to perform the conversion.

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

map_convert_values_to_milli(mapping, *keys)

Run to_milli on all specified keys’ values.

Parameters

• mapping (Dict[str, Any]) – Mutable mapping for which to apply the conversion

• *keys – Keys whose values to convert to milli. Uses to_milli to perform the conversion.

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

map_filter_none(mapping)

Remove all keys from the mapping whose values are None.

Parameters

mapping (MutableMapping[Any, Any]) – Mutable mapping to filter

Return type

None

Returns

This method mutates the provided mapping, it does not return anything.

map_rename_keys(mapping, **key_maps)

Rename keys of a mapping. This is just deleting the old key and assigning its value to the new key.

Parameters

• mapping (MutableMapping[str, Any]) – Mutable mapping to manipulate

• **key_maps – new -> old name mapping. The reason the mapping isn’t from old to new is that you may want to rename keys that aren’t python-friendly.

Return type

None

map_remove_keys(mapping, *keys)

Remove a number of keys (and their values) from a mapping.

Parameters

• mapping (MutableMapping[~KT, Any]) – Mapping to remove keys from.

• *keys – Keys to remove.

Return type

None

Returns

Nothing, the operation mutates the given mapping.