---
title: FilterOpNodes (v1.4)
description: API reference for qiskit.transpiler.passes.FilterOpNodes in qiskit v1.4
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/1.4/qiskit.transpiler.passes.FilterOpNodes
---

# FilterOpNodes

*class* `qiskit.transpiler.passes.FilterOpNodes(*args, **kwargs)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.4/qiskit/transpiler/passes/utils/filter_op_nodes.py#L24-L66)

Bases: [`TransformationPass`](/docs/api/qiskit/1.4/qiskit.transpiler.TransformationPass "qiskit.transpiler.basepasses.TransformationPass")

Remove all operations that match a filter function

This transformation pass is used to remove any operations that matches a the provided filter function.

**Parameters**

**predicate** – A given callable that will be passed the [`DAGOpNode`](/docs/api/qiskit/1.4/qiskit.dagcircuit.DAGOpNode "qiskit.dagcircuit.DAGOpNode") for each node in the [`DAGCircuit`](/docs/api/qiskit/1.4/qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit"). If the callable returns `True` the [`DAGOpNode`](/docs/api/qiskit/1.4/qiskit.dagcircuit.DAGOpNode "qiskit.dagcircuit.DAGOpNode") is retained in the circuit and if it returns `False` it is removed from the circuit.

**Example**

Filter out operations that are labeled `"foo"`

```python
from qiskit import QuantumCircuit
from qiskit.transpiler.passes import FilterOpNodes

circuit = QuantumCircuit(1)
circuit.x(0, label='foo')
circuit.barrier()
circuit.h(0)

circuit = FilterOpNodes(
    lambda node: getattr(node.op, "label") != "foo"
)(circuit)
circuit.draw('mpl')
```

![Circuit diagram output by the previous code.](https://eu-de.quantum.cloud.ibm.com/docs/images/api/qiskit/1.4/qiskit-transpiler-passes-FilterOpNodes-1.avif)

## Attributes

### is\_analysis\_pass

Check if the pass is an analysis pass.

If the pass is an AnalysisPass, that means that the pass can analyze the DAG and write the results of that analysis in the property set. Modifications on the DAG are not allowed by this kind of pass.

### is\_transformation\_pass

Check if the pass is a transformation pass.

If the pass is a TransformationPass, that means that the pass can manipulate the DAG, but cannot modify the property set (but it can be read).

## Methods

### execute

`execute(passmanager_ir, state, callback=None)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.4/qiskit/transpiler/basepasses.py#L189-L211)

Execute optimization task for input Qiskit IR.

**Parameters**

- **passmanager\_ir** ([*Any*](https://docs.python.org/3/library/typing.html#typing.Any)) – Qiskit IR to optimize.
- **state** ([*PassManagerState*](/docs/api/qiskit/1.4/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – State associated with workflow execution by the pass manager itself.
- **callback** ([*Callable*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Callable) *| None*) – A callback function which is caller per execution of optimization task.

**Returns**

Optimized Qiskit IR and state of the workflow.

**Return type**

[tuple](https://docs.python.org/3/library/stdtypes.html#tuple)\[[*Any*](https://docs.python.org/3/library/typing.html#typing.Any), [qiskit.passmanager.compilation\_status.PassManagerState](/docs/api/qiskit/1.4/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")]

### name

`name()`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.4/qiskit/passmanager/base_tasks.py#L68-L70)

Name of the pass.

**Return type**

[str](https://docs.python.org/3/library/stdtypes.html#str)

### run

`run(dag)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.4/qiskit/transpiler/passes/utils/filter_op_nodes.py#L62-L66)

Run the RemoveBarriers pass on dag.

**Parameters**

**dag** ([*DAGCircuit*](/docs/api/qiskit/1.4/qiskit.dagcircuit.DAGCircuit "qiskit._accelerate.circuit.DAGCircuit")) –

**Return type**

[*DAGCircuit*](/docs/api/qiskit/1.4/qiskit.dagcircuit.DAGCircuit "qiskit._accelerate.circuit.DAGCircuit")

### update\_status

`update_status(state, run_state)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.4/qiskit/transpiler/basepasses.py#L213-L221)

Update workflow status.

**Parameters**

- **state** ([*PassManagerState*](/docs/api/qiskit/1.4/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – Pass manager state to update.
- **run\_state** (*RunState*) – Completion status of current task.

**Returns**

Updated pass manager state.

**Return type**

[*PassManagerState*](/docs/api/qiskit/1.4/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")