Skip to main content
Version: Python

cum_prod

cum_prod calculates a cumulative product in an update_by table operation.

Syntax​

cum_prod(cols: list[str]) -> UpdateByOperation

Parameters​

ParameterTypeDescription
colslist[str]

The column(s) to be operated on. These can include expressions to rename the output columns (e.g., NewCol = Col). If None, the cumulative product is calculated for all applicable columns in the table.

Returns​

An UpdateByOperation to be used in an update_by table operation.

Examples​

The following example performs an update_by on the source table using the cum_prod operation. No grouping columns are given, so the cumulative product is calculated across all rows of the table.

from deephaven.updateby import cum_prod
from deephaven import empty_table

source = empty_table(10).update(["Letter = (i % 2 == 0) ? `A` : `B`", "X = i + 1"])

result = source.update_by(ops=cum_prod(cols=["ProdX = X"]), by=[])

The following example builds on the previous by specifying Letter as a grouping column. Thus, the cumulative product in the result table is calculated on a per-letter basis.

from deephaven.updateby import cum_prod
from deephaven import empty_table

source = empty_table(10).update(["Letter = (i % 2 == 0) ? `A` : `B`", "X = i + 1"])

result = source.update_by(ops=cum_prod(cols=["CumX = X"]), by=["Letter"])

The following example builds on the previous by calculating the cumulative product of two columns using the same UpdateByOperation.

from deephaven.updateby import cum_prod
from deephaven import empty_table

source = empty_table(10).update(
    ["Letter = (i % 2 == 0) ? `A` : `B`", "X = i + 1", "Y = randomInt(1, 7)"]
)

result = source.update_by(ops=cum_prod(cols=["ProdX = X", "ProdY = Y"]), by=["Letter"])

The following example builds on the previous by specifying two grouping columns: Letter and Truth. Thus, groups consist of unique combinations of letter in Letter and boolean in Truth.

from deephaven.updateby import cum_prod
from deephaven import empty_table

source = empty_table(10).update(
    [
        "Letter = (i % 2 == 0) ? `A` : `B`",
        "Truth = randomBool()",
        "X = i + 1",
        "Y = randomInt(1, 7)",
    ]
)

result = source.update_by(
    ops=cum_prod(cols=["ProdX = X", "ProdY = Y"]), by=["Letter", "Truth"]
)