keras-team/keras · error · TypeError

A Keras Variable cannot be used as a boolean.

Error message

A Keras Variable cannot be used as a boolean.

What it means

Error "A Keras Variable cannot be used as a boolean." thrown in keras-team/keras.

Source

Thrown at keras/src/backend/common/variables.py:452

        return int(self.value)

    def __float__(self):
        if self.ndim > 0:
            raise TypeError(
                "Only scalar arrays can be converted to Python scalars. "
                f"Got: shape={self.shape}"
            )
        return float(self.value)

    def __array__(self, dtype=None):
        # We can't directly use self.value.__array__ here because of scalar.
        # Numpy require this method to return as array like object. In the case
        # of scalar, it will fail the type checking from numpy. We need to
        # return a 0d array via numpy.
        return np.asarray(self.value.__array__(dtype))

    def __bool__(self):
        raise TypeError("A Keras Variable cannot be used as a boolean.")

    def __neg__(self):
        return self.value.__neg__()

    def __pos__(self):
        return self.value

    def __abs__(self):
        return self.value.__abs__()

    def __invert__(self):
        return self.value.__invert__()

    def __eq__(self, other):
        return backend.numpy.equal(self.value, other)

    def __ne__(self, other):
        return backend.numpy.not_equal(self.value, other)

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/backend/common/variables.py:452 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of keras-team/keras@7a34a03db6 (2026-08-25). Data as JSON: /api/errors/1c27e09503d50477. Report an issue: GitHub.