arbitrary_element(iterable)

This is most useful for "peeking" at an arbitrary element of a set, but can be used for any list, dictionary, etc., as well.

Notes

This function does not return a random element. If iterable is ordered, sequential calls will return the same value:

>>> l = [1, 2, 3]
>>> nx.utils.arbitrary_element(l)
1
>>> nx.utils.arbitrary_element(l)
1

Parameters

iterable : `abc.collections.Iterable` instance

Any object that implements __iter__ , e.g. set, dict, list, tuple, etc.

Raises

ValueError

If iterable is an iterator (because the current implementation of this function would consume an element from the iterator).

Returns

The object that results from ``next(iter(iterable))``

Returns an arbitrary element of iterable without removing it.

Examples

Arbitrary elements from common Iterable objects:

>>> nx.utils.arbitrary_element([1, 2, 3])  # list
1

>>> nx.utils.arbitrary_element((1, 2, 3))  # tuple
1

>>> nx.utils.arbitrary_element({1, 2, 3})  # set
1

>>> d = {k: v for k, v in zip([1, 2, 3], [3, 2, 1])}
... nx.utils.arbitrary_element(d)  # dict_keys
1

>>> nx.utils.arbitrary_element(d.values())   # dict values
3

:None:None:`str` is also an Iterable:

>>> nx.utils.arbitrary_element("hello")
'h'

ValueError is raised if iterable is an iterator:

This example is valid syntax, but raise an exception at execution

>>> iterator = iter([1, 2, 3])  # Iterator, *not* Iterable
... nx.utils.arbitrary_element(iterator)
Traceback (most recent call last):
    ...
ValueError: cannot return an arbitrary item from an iterator

See :

Back References

The following pages refer to to this document either explicitly or contain code examples using this.

networkx.utils.misc.arbitrary_element

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GitHub : /networkx/utils/misc.py#320
type: <class 'function'>
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