Aggregations

EZTable allows the contents of a table to be grouped according to the values of one or more column.

Internally the aggregation function splits the main table into a number of smaller sub-tables, according to the group-columns.

In this example we are grouping by two of the columns, and using the len function to get the length of each resulting sub-table.

Aggregations are specified as a triple containing name, type and function.

The function must be a callable which takes a subtable as it’s input and returns a value of the type specfied in the 2nd column.

>>> from eztable import table_literal
Warning: FastBinaryTree not available, using Python version BinaryTree.
Warning: FastAVLTree not available, using Python version AVLTree.
Warning: FastRBTree not available, using Python version RBTree.
>>> t = table_literal("""
... | Attack(str)   | Pokemon(str) | Level Obtained(int) | Attack Type(str) |
... | Thunder Shock | Pikachu      | 1                   | Electric         |
... | Tackle        | Pikachu      | 1                   | Normal           |
... | Tail Whip     | Pikachu      | 1                   | Normal           |
... | Growl         | Pikachu      | 5                   | Normal           |
... | Quick Attack  | Pikachu      | 10                  | Normal           |
... | Thunder Wave  | Pikachu      | 13                  | Electric         |
... | Electro Ball  | Pikachu      | 18                  | Electric         |
... | Charm         | Pikachu      | 0                   | Fairy            |
... | Sweet Kiss    | Pikachu      | 0                   | Fairy            |
... """)
>>>
>>> agg = t.aggregate(
...     keys=('Pokemon', 'Attack Type'),
...     aggregations=[
...         ('Count', int, len)
...     ]
... )
>>>
>>> print(agg)
| Pokemon (str) | Attack Type (str) | Count (int) |
| Pikachu       | Electric          | 3           |
| Pikachu       | Normal            | 4           |
| Pikachu       | Fairy             | 2           |
>>>