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Counts

class qiskit.result.Counts(data, time_taken=None, creg_sizes=None, memory_slots=None)

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Bases: dict

A class to store a counts result from a circuit execution.

Build a counts object

Parameters

  • data (dict) –

    The dictionary input for the counts. Where the keys represent a measured classical value and the value is an integer the number of shots with that result. The keys can be one of several formats:

    • A hexadecimal string of the form '0x4a'
    • A bit string prefixed with 0b for example '0b1011'
    • A bit string formatted across register and memory slots. For example, '00 10'.
    • A dit string, for example '02'. Note for objects created with dit strings the creg_sizes and memory_slots kwargs don’t work and hex_outcomes() and int_outcomes() also do not work.
  • time_taken (float) – The duration of the experiment that generated the counts in seconds.

  • creg_sizes (list) – a nested list where the inner element is a list of tuples containing both the classical register name and classical register size. For example, [('c_reg', 2), ('my_creg', 4)].

  • memory_slots (int) – The number of total memory_slots in the experiment.

Raises

  • TypeError – If the input key type is not an int or str.
  • QiskitError – If a dit string key is input with creg_sizes and/or memory_slots.

Attributes

bitstring_regex

Default value: re.compile('^[01\\s]+$')


Methods

clear

clear() → None.  Remove all items from D.

copy

copy() → a shallow copy of D

fromkeys

fromkeys(value=None, /)

Create a new dictionary with keys from iterable and values set to value.

get

get(key, default=None, /)

Return the value for key if key is in the dictionary, else default.

hex_outcomes

hex_outcomes()

GitHub

Return a counts dictionary with hexadecimal string keys

Returns

A dictionary with the keys as hexadecimal strings instead of

bitstrings

Return type

dict

Raises

QiskitError – If the Counts object contains counts for dit strings

int_outcomes

int_outcomes()

GitHub

Build a counts dictionary with integer keys instead of count strings

Returns

A dictionary with the keys as integers instead of bitstrings

Return type

dict

Raises

QiskitError – If the Counts object contains counts for dit strings

items

items() → a set-like object providing a view on D's items

keys

keys() → a set-like object providing a view on D's keys

most_frequent

most_frequent()

GitHub

Return the most frequent count

Returns

The bit string for the most frequent result

Return type

str

Raises

QiskitError – when there is >1 count with the same max counts, or an empty object.

pop

pop(k[, d]) → v, remove specified key and return the corresponding value.

If key is not found, default is returned if given, otherwise KeyError is raised

popitem

popitem()

Remove and return a (key, value) pair as a 2-tuple.

Pairs are returned in LIFO (last-in, first-out) order. Raises KeyError if the dict is empty.

setdefault

setdefault(key, default=None, /)

Insert key with a value of default if key is not in the dictionary.

Return the value for key if key is in the dictionary, else default.

shots

shots()

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Return the number of shots

update

update([E, ]**F) → None.  Update D from dict/iterable E and F.

If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]

values

values() → an object providing a view on D's values

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