where()

@overload
atoti.where(
    condition: ColumnCondition,
    true_value: ColumnConvertible,
    false_value: ColumnConvertible | None = None,
    /,
) → Operation[ColumnIdentifier]

@overload
atoti.where(
    condition: VariableMeasureConvertible,
    true_value: MeasureConvertible,
    false_value: MeasureConvertible | None = None,
    /,
) → MeasureDefinition

@overload
atoti.where(
    condition_to_value: Mapping[VariableMeasureConvertible, MeasureConvertible],
    /,
    *,
    default: MeasureConvertible | None = None,
) → MeasureDefinition

• Where the condition is True, the new measure will be equal to true_value.
• Where the condition is False, the new measure will be equal to false_value.

• Measures compared to anything measure-like:
  m["Test"] == 20
  
• Levels compared to levels, (if the level is not expressed, it is considered None):
  l["source"] == l["destination"]
  
• Levels compared to constants of the same type:
  l["city"] == "Paris"
  l["date"] > datetime.date(2020, 1, 1)
  l["age"] <= 18
  
• A conjunction or disjunction of conditions using the & operator or | operator:
  (m["Test"] == 20) & (l["city"] == "Paris")
  (l["Country"] == "USA") | (l["Currency"] == "USD")
  

>>> df = pd.DataFrame(
...     columns=["Id", "City", "Value"],
...     data=[
...         (0, "Paris", 1.0),
...         (1, "Paris", 2.0),
...         (2, "London", 3.0),
...         (3, "London", 4.0),
...         (4, "Paris", 5.0),
...     ],
... )
>>> table = session.read_pandas(df, keys={"Id"}, table_name="filter example")
>>> cube = session.create_cube(table)
>>> l, m = cube.levels, cube.measures
>>> m["Paris value"] = tt.where(l["City"] == "Paris", m["Value.SUM"], 0)
>>> cube.query(m["Paris value"], levels=[l["City"]])
       Paris value
City
London         .00
Paris         8.00

>>> m["Value.RECAP"] = tt.where(
...     {
...         m["Value.SUM"] < 3: "less than 3",
...         m["Value.SUM"] <= 3: "less than or equal to 3",
...         m["Value.SUM"]
...         == 3: "equal to 3",  # never used because of the broader condition before
...     },
...     default="more than 3",
... )
>>> cube.query(m["Value.SUM"], m["Value.RECAP"], levels=[l["Id"]])
   Value.SUM              Value.RECAP
Id
0       1.00              less than 3
1       2.00              less than 3
2       3.00  less than or equal to 3
3       4.00              more than 3
4       5.00              more than 3

​

Parameters

​

condition

VariableMeasureConvertible

​

true_value

MeasureConvertible

​

false_value

MeasureConvertible | None

​

condition_to_value

Mapping[VariableMeasureConvertible, MeasureConvertible]

​

default

MeasureConvertible | None