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
.
source = newTable(
intCol("IntegerColumn", 1, 2, -2, -1)
)
result = source.update("Abs = abs(IntegerColumn)")
- result
- source
Example: parseInt
This example shows how to convert a column of numeric strings into integers using parseInt
.
source = newTable(
stringCol("StringColumn", "1", "2", "-2", "-1")
)
result = source.update("IntegerColumn = parseInt(StringColumn)")
- result
- source
Example: parseInstant
This example shows how to convert a column of date-time strings to Instant objects using parseInstant
.
source = newTable(
stringCol("DateTimeStrings", "2020-01-01T00:00:00 ET", "2020-01-02T00:00:00 ET", "2020-01-03T00:00:00 ET")
)
result = source.update("DateTimes = parseInstant(DateTimeStrings)")
- result
- source
Example: and
This example shows how to compute the logical AND of a group of columns of booleans using and
.
source = newTable(
booleanCol("A", true, true, true),
booleanCol("B", true, true, false),
booleanCol("C", true, false, true)
)
result = source.update("IsOk = and(A, B, C)")
- result
- source
Example: absAvg
and avg
This example shows how to compute the average of the absolute value of integers in a column using absAverage
.
source = newTable(
intCol("A", -1, 2, 3),
intCol("B", 1, -2, 3),
intCol("C", 1, 2, -3),
)
result = source.update("AbsAvg = absAvg(A, B, C)", "Avg = avg(A, B, C)")
- result
- source