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# Quantum Circuit Formats
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Qiskit supports import/export of quantum circuits in OpenQASM 2.0/3.0 and QPY binary formats for interoperability with other quantum computing tools and long-term circuit storage.
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## Capabilities
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### OpenQASM 2.0 Interface
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```python { .api }
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# qiskit.qasm2 module
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def load(filename):
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    """Load OpenQASM 2.0 circuit from file."""
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def loads(qasm_str):
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    """Load OpenQASM 2.0 circuit from string."""
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def dump(circuit, filename):
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    """Export circuit to OpenQASM 2.0 file."""
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def dumps(circuit):
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    """Export circuit to OpenQASM 2.0 string."""
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```
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### OpenQASM 3.0 Interface
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```python { .api }
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# qiskit.qasm3 module  
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def load(filename):
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    """Load OpenQASM 3.0 circuit from file."""
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def loads(qasm_str):
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    """Load OpenQASM 3.0 circuit from string."""
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def dump(circuit, filename):
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    """Export circuit to OpenQASM 3.0 file."""
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def dumps(circuit):
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    """Export circuit to OpenQASM 3.0 string."""
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```
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### QPY Binary Format
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```python { .api }
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# qiskit.qpy module
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def dump(circuits, file_obj):
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    """Serialize quantum circuits to QPY binary format."""
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def load(file_obj):
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    """Deserialize quantum circuits from QPY binary format."""
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def get_qpy_version():
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    """Get current QPY format version."""
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QPY_VERSION: int = 12
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QPY_COMPATIBILITY_VERSION: int = 10
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```
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### Usage Examples
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```python
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from qiskit import QuantumCircuit
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from qiskit import qasm2, qasm3, qpy
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circuit = QuantumCircuit(2, 2)
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circuit.h(0)
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circuit.cx(0, 1)
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circuit.measure_all()
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# QASM export/import
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qasm2_str = qasm2.dumps(circuit)
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loaded_circuit = qasm2.loads(qasm2_str)
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# QPY binary format
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with open('circuit.qpy', 'wb') as f:
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    qpy.dump([circuit], f)
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with open('circuit.qpy', 'rb') as f:
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    loaded_circuits = qpy.load(f)
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```