README.md

Readme

Quick introduction

tab2dict aims to solve a common problem in developing scientific software (i.e., models): How to manage data with multiple subscripts, e.g., importing them into the model, saving them to result files, etc.

For example, $N_{s,bt}$ denotes the number of buildings in sector $s$ and with the type $bt$. It is an input parameter of your model. Then, using tab2dict, you can do as follows:

First, create a .xlsx or .csv file as follows to save the data:

id_sector	id_building_type	unit	value
1	1	count	10000
1	2	count	12000
2	3	count	500
2	6	count	3000
2	7	count	200
3	3	count	300
3	4	count	2000
4	5	count	2500
5	3	count	800
5	5	count	100
5	7	count	400

Second, use the following code to import the data into the model as an instance of TabDict:

from tab2dict import TabDict

building_stock = TabDict.from_file("Data_BuildingStock.xlsx")

Third, create a model-specific class by inheriting the TabKey class provided by tab2dict, with all the relevant id_xxx as its attributes.

from typing import Optional
from tab2dict import TabKey

class BuildingTabKey(TabKey):
    def __init__(
        self,
        id_sector: Optional[int] = None,
        id_building_type: Optional[int] = None,
        time_year: Optional[int] = None,
    ):
        self.id_sector = id_sector
        self.id_building_type = id_building_type
        self.time_year = time_year

Fourth, create an instance of the BuildingTabKey class to get data from the building_stock.

tkey = BuildingTabKey(id_sector=1, id_building_type=2)
a = building_stock.get_item(tkey) # -> 12000

There are two main advantages of using tab2dict:

• As implied by the name, TabDict use dict to save data. So, the speed of get_item() is fast. But of course, the input data will all be loaded and take some space in the memory.
• It allows the users to adapt the input tables relatively freely (e.g., adding or removing index columns) with limited changes in the code. This is a good feature especially useful in the agent-based models. Because each agent can be assigned with its own tabkey, knowing all the id_xxx more than necessary for individual tables or tabdicts. Then there can be no necessary changes in the code when one more "subscript (id_xxx column)" is added to a parameter in is input table.

You can find more detailed introduction in the following sections as well as in the test folder of the project. Hope tab2dict can make your life easier in developing models!

Getting started

Most functions of tab2dict are clearly shown in the test files. Below is a quick introduction of the main points.

TabDict

There are three types of predefined input tables that can be loaded and converted to TabDict instances:

• "ID" tables named as "ID_XXX"
• "Relation" tables named as "Relation_XXX"
• "Data" tables named as "Data_XXX"

In each type of tables, the column names must follow the convention shown in the examples below:

First, in the "ID" tables:

• The name of the first column must start with id_, e.g., id_sector or id_building_type.
• The name of the second column must be name.

Example: ID_Sector.xlsx

id_sector	name
1	residential
2	manufacturing
3	retail
4	hotel and restaurant
5	public administration

Example: ID_BuildingType.xlsx

id_building_type	name
1	single family house
2	multiple family house
3	office
4	Shopping mall
5	accommodation and restaurant buildings
6	production buildings
7	other buildings

Second, in the "Relation" tables:

• There can only be two columns, showing the relation between the two indexes.

Example: Relation_Sector_BuildingType.xlsx

id_sector	id_building_type
1	1
1	2
2	3
2	6
2	7
3	3
3	4
4	5
5	3
5	5
5	7

Third, in the "Data" tables:

• tab2dict supports multiple index columns in a "Data" table. And, apart from id_, tab2dict also has time_ as a known prefix for index column names, designed for timeseries data. But, there is no third known prefix. So, all index columns must have names starting with either id_ or time_. Or, they will not be identified as index columns.
• The unit column is optional but suggested to be included.
• By default, the name of the last "value column" is value. tab2dict also allows users to define other names for the "value column". Besides, the users can have multiple value columns in one "Data" table. For such tables, users should specify the value_column_name when loading the table and converting it to an instance of TabDict (example below).

Example: Data_BuildingStock.xlsx

id_sector	id_building_type	unit	value
1	1	count	10000
1	2	count	12000
2	3	count	500
2	6	count	3000
2	7	count	200
3	3	count	300
3	4	count	2000
4	5	count	2500
5	3	count	800
5	5	count	100
5	7	count	400

Example: Data_EnergyIntensityIndex.xlsx

id_building_type	time_year	unit	value
1	2020	Euros	1
1	2030	Euros	0.99
1	2040	Euros	0.98
1	2050	Euros	0.97
2	2020	Euros	1
2	2030	Euros	0.98
2	2040	Euros	0.96
2	2050	Euros	0.94
3	2020	Euros	1
3	2030	Euros	0.97
3	2040	Euros	0.94
3	2050	Euros	0.91
4	2020	Euros	1
4	2030	Euros	0.96
4	2040	Euros	0.92
4	2050	Euros	0.88
5	2020	Euros	1
5	2030	Euros	0.95
5	2040	Euros	0.9
5	2050	Euros	0.85
6	2020	Euros	1
6	2030	Euros	0.94
6	2040	Euros	0.88
6	2050	Euros	0.82
7	2020	Euros	1
7	2030	Euros	0.93
7	2040	Euros	0.86
7	2050	Euros	0.79

Example: Data_BuildingParameter.xlsx

id_sector	id_building_type	unit	a	b	c
1	1	count	1	10	100
1	2	count	2	20	200
2	3	count	3	30	300
2	6	count	4	40	400
2	7	count	5	50	500
3	3	count	6	60	600
3	4	count	7	70	700
4	5	count	8	80	800
5	3	count	9	90	900
5	5	count	10	100	1000
5	7	count	11	110	1100

TabKey

tab2dict provides the base class TabKey that has to be inherited and extended according to the input table columns.

from typing import Optional
from tab2dict import TabKey

class BuildingTabKey(TabKey):
    def __init__(
        self,
        id_sector: Optional[int] = None,
        id_building_type: Optional[int] = None,
        time_year: Optional[int] = None,
    ):
        self.id_sector = id_sector
        self.id_building_type = id_building_type
        self.time_year = time_year

As shown, the attributes of the BuildingTabKey class are the index column names in the input tables. As mentioned, they must always start with id_ or time_.

Examples

Load data

Users can load and convert a data file to a TabDict instance (tdict) by calling the from_file function. The index columns will be automatically identified and recorded as its key_cols.

from tab2dict import TabDict

sectors = TabDict.from_file("ID_Sector.xlsx")
building_types = TabDict.from_file("ID_BuildingType.xlsx")
relation_sector_building_type = TabDict.from_file("Relation_Sector_BuildingType.xlsx")
building_stock = TabDict.from_file("Data_BuildingStock.xlsx")
energy_intensity_index = TabDict.from_file("Data_EnergyIntensityIndex.xlsx")
building_parameter_a = TabDict.from_file("Data_BuildingParameter.xlsx", value_column_name="a")
building_parameter_b = TabDict.from_file("Data_BuildingParameter.xlsx", value_column_name="b")
building_parameter_c = TabDict.from_file("Data_BuildingParameter.xlsx", value_column_name="c")

Besides, users can also use the from_dataframe function to create a tdict, but the tdict_type must be specified as ID, Relation, or Data.

from tab2dict import TabDict
import pandas as pd

df = pd.DataFrame({
    "id_sector": [1, 1, 2, 3, 4],
    "id_building_type": [1, 2, 6, 4, 5],
    "unit": "count",
    "value": [10, 20, 30, 40, 50]
})
building_number = TabDict.from_dataframe(df=df, tdict_type="Data")

Get data

With a TabKey instance (tkey), users can fetch data from a tdict, as long as the tkey has values for the tdict's key_cols. The tkey can know more than necessary, which supports the following flexibilities

• removing an index column from an input table will not cause code changes;
• adding a new index column in the input table may neither, as long as the tkey has value for the added column.

tkey = BuildingTabKey(id_sector=1, id_building_type=2, time_year=2030)
sectors.get_item(tkey) # -> "residential"
building_types.get_item(tkey) # -> "multiple family house"
relation_sector_building_type.get_item(tkey) # -> [1, 2]
building_stock.get_item(tkey) # -> 12000
energy_intensity_index.get_item(tkey) # -> 0.98
building_parameter_a.get_item(tkey) # -> 2
building_parameter_b.get_item(tkey) # -> 20
building_parameter_c.get_item(tkey) # -> 200
building_number.get_item(tkey) # -> 20

Collect data

Finally, users can also create an empty tdict by calling the create_empty_data_tdict function. The key_cols must be speficied. The type of the tdict is Data. In practice, the empty data tdicts can be used for collecting model results by calling the set_item or accumulate_item functions.

from tab2dict import TabDict

building_number_result = TabDict.create_empty_data_tdict(key_cols=["id_sector", "id_building_type"])
tkey = BuildingTabKey(id_sector=1, id_building_type=1)
building_number_result.set_item(tkey, 10000)
tkey.id_building_type = 2
building_number_result.set_item(tkey, 20000)
building_number_result.accumulate_item(tkey, 20000)
tkey.id_building_type = 3
building_number_result.accumulate_item(tkey, 30000)


tkey.id_building_type = 1
building_number_result.get_item(tkey) # -> 10000
tkey.id_building_type = 2
building_number_result.get_item(tkey) # -> 40000
tkey.id_building_type = 3
building_number_result.get_item(tkey) # -> 30000

Dependencies

• Python: 3.8 or later

package	user	contributor
pandas	✓	✓
openpyxl	✓	✓
pytest		✓
pytest-cov		✓
black		✓
pylint		✓

Version History

• 29.12.2023 - Initial Release (v0.0.1)

License

Author: @SongminYu.

License: MIT.