tf.keras.backend.ndim

Returns the number of axes in a tensor, as an integer.

x Tensor or variable.

Integer (scalar), number of axes.

Examples:

input = tf.keras.backend.placeholder(shape=(2, 4, 5))
val = np.array([[1, 2], [3, 4]])
kvar = tf.keras.backend.variable(value=val)
tf.keras.backend.ndim(input)
3
tf.keras.backend.ndim(kvar)
2