---
title: iteration (latest version)
description: API reference for qiskit_addon_cutting.utils.iteration in the latest version of qiskit-addon-cutting
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit-addon-cutting/utils-iteration
---

# Iteration utilities

`qiskit_addon_cutting.utils.iteration`

Iteration utilities.

### unique\_by\_id

`unique_by_id(iterable, /)`

[GitHub](https://github.com/Qiskit/qiskit-addon-cutting/tree/stable/0.10/qiskit_addon_cutting/utils/iteration.py)

Return unique objects in `iterable`, by identity.

```python
>>> a = {0}
>>> list(unique_by_id([a, a]))
[{0}]
:rtype: :sphinx_autodoc_typehints_type:`\:py\:class\:\`\~collections.abc.ValuesView\``
```

```python
>>> list(unique_by_id([a, a.copy()]))
[{0}, {0}]
```

**Parameters**

**iterable** ([*Iterable*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Iterable))

**Return type**

[*ValuesView*](https://docs.python.org/3/library/collections.abc.html#collections.abc.ValuesView)

### unique\_by\_eq

`unique_by_eq(iterable, /)`

[GitHub](https://github.com/Qiskit/qiskit-addon-cutting/tree/stable/0.10/qiskit_addon_cutting/utils/iteration.py)

Return unique objects in `iterable`, by equality.

This function is only appropriate if (i) there are a small number of objects, and (ii) the objects are not guaranteed to be hashable. Otherwise, a `dict` or `set` is a better choice.

This function may potentially make a comparison between all pairs of elements, so it executes in $O(n^2)$ time in the worst case, in contrast to a `dict` or `set`, both of which can be constructed in $O(n)$ time.

```python
>>> a = {0}
>>> list(unique_by_eq([a, a]))
[{0}]
:rtype: :sphinx_autodoc_typehints_type:`\:py\:class\:\`list\``
```

```python
>>> list(unique_by_eq([a, a.copy()]))
[{0}]
```

**Parameters**

**iterable** ([*Iterable*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Iterable))

**Return type**

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