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Version: Python

Use objects in query strings

This guide will show you how to work with objects in your query strings.

When performing complex analyses, objects are an invaluable tool. Objects can contain related data and provide an easy way to access data from one source to make your program more logical or streamlined.

The Deephaven Query Language natively supports objects, allowing users to pass them, their attributes, and their methods into query strings.

Power of objects in code​

Objects are designed to hold information or values. In the following example, operators are used with objects to assign values.

Here, we have two objects, and each object holds two values and a custom method. When we call one of these objects, its specific values and methods are utilized without having to pass extra parameters.

from deephaven import empty_table


class SimpleObj:
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def compute(self):
        return self.a + self.b


class OtherObj:
    def __init__(self, a, b):
        self.a = a
        self.b = b

    def compute(self):
        return 2 * self.a + 2 * self.b


obj1 = SimpleObj(1, 2)
obj2 = OtherObj(3, 4)

result = empty_table(5).update(
    formulas=["X = obj1.a", "Y = obj1.compute()", "M = obj2.a", "N = obj2.compute()"]
)

Poorly written code​

If we didn't use objects, our code could get confusing and cumbersome.

In the following example, we do a similar operation as above, but without the power of objects. Notice that the compute methods require us to track the parameters, and pass them in every time we need to perform these operations.

from deephaven import empty_table


def compute1(value_a, value_b):
    return value_a + value_b


def compute2(value_a, value_b):
    return 2 * value_a + 2 * value_b


a1 = 1
b1 = 2
a2 = 3
b2 = 4

result = empty_table(5).update(
    formulas=["X = a1", "Y = compute1(a1, b1)", "M = a2", "N = compute2(a2, b2)"]
)

Use the power of objects in the Deephaven Query Language to make your queries more powerful and concise.