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Version: Python

liveness_scope

liveness_scope is a Python method for creating and opening a LivenessScope for running a block of code. Use this function to wrap a block of code using a with statement. For the duration of the with block, the liveness scope will be open and any liveness referents created will be automatically managed by it.

Syntax​

scope = liveness_scope()

Parameters​

None.

Returns​

A LivenessScope.

Examples​

The method can be used in a with block to encapsulate code that produces ticking data. In the example below, table is explicitly preserved outside of the with block. ticking_table is cleaned up once the with block is exited.

from deephaven.liveness_scope import liveness_scope

with liveness_scope() as scope:
    ticking_table = some_ticking_source()
    table = ticking_table.snapshot().join(table=other_ticking_table, on=...)
    scope.preserve(table)
return table

It can also be used as a decorator to achieve a similar result.

@liveness_scope
def get_values():
    ticking_table = some_ticking_source().last_by("Sym")
    return dhnp.to_numpy(ticking_table)