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cirq.measurement_key_name

Get the single measurement key for the given value.

cirq.measurement_key_name(
    val: Any, default: Any = RaiseTypeErrorIfNotProvided
)

Args
`val`	The value which has one measurement key.
`default`	Determines the fallback behavior when `val` doesn't have a measurement key. If `default` is not set, a TypeError is raised. If default is set to a value, that value is returned if the value does not have `_measurement_key_name_`.

Returns
If `val` has a `_measurement_key_name_` method and its result is not `NotImplemented`, that result is returned. Otherwise, if a default value was specified, the default value is returned.

Raises
`TypeError`	`val` doesn't have a _measurement_keyname method (or that method returned NotImplemented) and also no default value was specified.
`ValueError`	`val` has multiple measurement keys.

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Last updated 2025-08-14 UTC.

Args