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Version: Java (Groovy)

AggMed

AggMed returns an aggregator that computes the median value, within an aggregation group, for each input column.

Syntax​

AggMed(average, pairs...)
AggMed(pairs...)

Parameters​

ParameterTypeDescription
pairsString...

The source column(s) for the calculations.

  • "X" will output the median value in the X column for each group.
  • "Y = X" will output the median value in the X column for each group and rename it to Y.
  • "X, A = B" will output the median value in the X column for each group and the median value in the B column while renaming it to A.
averageboolean

Whether to average the two middle values for even-sized result sets of numeric types. If no value is given, the default behavior is to average the two center values. See AggSpecMedian.

caution

If an aggregation does not rename the resulting column, the aggregation column will appear in the output table, not the input column. If multiple aggregations on the same column do not rename the resulting columns, an error will result, because the aggregations are trying to create multiple columns with the same name. For example, in table.aggBy([agg.AggSum(“X”), agg.AggAvg(“X”)]), both the sum and the average aggregators produce column X, which results in an error.

Returns​

An aggregator that computes the median value, within an aggregation group, for each input column.

Examples​

In this example, AggMed returns the median Number value as grouped by X.

import static io.deephaven.api.agg.Aggregation.AggMed

source = newTable(
    stringCol("X", "A", "B", "A", "C", "B", "A", "B", "B", "C"),
    stringCol("Y", "M", "N", "O", "N", "P", "M", "O", "P", "M"),
    intCol("Number", 55, 76, 20, 130, 230, 50, 73, 137, 214),
)

result = source.aggBy([AggMed("Number")], "X")

In this example, AggMed returns the median Number value (renamed to Z), as grouped by X.

import static io.deephaven.api.agg.Aggregation.AggMed

source = newTable(
    stringCol("X", "A", "B", "A", "C", "B", "A", "B", "B", "C"),
    stringCol("Y", "M", "N", "O", "N", "P", "M", "O", "P", "M"),
    intCol("Number", 55, 76, 20, 130, 230, 50, 73, 137, 214),
)

result = source.aggBy([AggMed("Z = Number")], "X")

In this example, AggMed returns the median Number, as grouped by X and Y.

import static io.deephaven.api.agg.Aggregation.AggMed

source = newTable(
    stringCol("X", "A", "B", "A", "C", "B", "A", "B", "B", "C"),
    stringCol("Y", "M", "P", "O", "N", "P", "M", "O", "P", "N"),
    intCol("Number", 55, 76, 20, 130, 230, 50, 73, 137, 214),
)

result = source.aggBy([AggMed("Number")], "X", "Y")

In this example, AggMed returns the median Number, and AggMax returns the maximum Number, as grouped by X.

import static io.deephaven.api.agg.Aggregation.AggMed
import static io.deephaven.api.agg.Aggregation.AggMax

source = newTable(
    stringCol("X", "A", "B", "A", "C", "B", "A", "B", "B", "C"),
    stringCol("Y", "M", "P", "O", "N", "P", "M", "O", "P", "N"),
    intCol("Number", 55, 76, 20, 130, 230, 50, 73, 137, 214),
)

result = source.aggBy([AggMed("MedNumber = Number"),AggMax("MaxNumber = Number")], "X")