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Version: Python

How to use Deephaven's built-in query language functions

Deephaven's query language has many functions that are automatically imported for use. These functions can be used in any update (or similar) operation without any imports needed. Since these functions are Java functions, they are fast and don't require any data type casting.

This guide shows a few examples of using these automatically imported functions. The auto import query language functions reference shows all of the Java classes whose functions are automatically imported for use.

Example: abs

This example shows how to convert a column of integers into a column of the absolute values of the integers using abs.

from deephaven import new_table
from deephaven.column import int_col

source = new_table([
int_col("IntegerColumn", [1, 2, -2, -1])
])
result = source.update(["Abs = abs(IntegerColumn)"])

Example: parseInt

This example shows how to convert a column of numeric strings into integers using parseInt.

from deephaven import new_table
from deephaven.column import string_col

source = new_table([
string_col("StringColumn", ["1", "2", "-2", "-1"])
])
result = source.update(["IntegerColumn = parseInt(StringColumn)"])

Example: convertDateTime

This example shows how to convert a column of DateTime strings to DateTime objects using convertDateTime.

from deephaven import new_table
from deephaven.column import string_col

source = new_table([
string_col("DateTimeStrings", ["2020-01-01T00:00:00 NY", "2020-01-02T00:00:00 NY", "2020-01-03T00:00:00 NY"])
])

result = source.update(["DateTimes = convertDateTime(DateTimeStrings)"])

Example: and

This example shows how to compute the logical AND of a group of columns of booleans using and.

from deephaven import new_table
from deephaven.column import bool_col

source = new_table([
bool_col("A", [True, True, True]),
bool_col("B", [True, True, False]),
bool_col("C", [True, False, True])
])
result = source.update(["IsOk = and(A, B, C)"])

Example: absAvg and avg

This example shows how to compute the average of the absolute value of integers in a column using absAverage.

from deephaven import new_table
from deephaven.column import int_col

source = new_table([
int_col("A", [-1, 2, 3]),
int_col("B", [1, -2, 3]),
int_col("C", [1, 2, -3]),
])
result = source.update(["AbsAvg = absAvg(A, B, C)", "Avg = avg(A, B, C)"])