# I don't get anything when calling circuit.draw()

I'm following the YouTube tutorials for Programming on Quantum Computers and I've completed everything until I reach circuit.draw() since I don't get $$|0\rangle$$ or 0 next to q or c. Here's my code:

from qiskit import *

qr = QuantumRegister(2)
cr = ClassicalRegister(2)
circuit = QuantumCircuit(qr, cr)

%matplotlib inline

circuit.draw()

[
q0_0:
q0_1:
c0: 2/
]


and so when I attempt an H gate, I receive the error 'QuantumRegister' object is not callable:

circuit.h(qr(0))

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-55-c8b4318b743b> in <module>
----> 1 circuit.h(qr(0))

TypeError: 'QuantumRegister' object is not callable


There is probably a change on the default arguments of draw() function. To reproduce the same visualization as on the youtube video, try:

circuit.draw(initial_state=True,
cregbundle=False)


circuit.h(qr[0])

• Awesome! Thanks a lot. Where can I see other changes as to avoid problems like this in the future? – Riad Dajani Oct 12 '20 at 13:15
• Qiskit Documentation is the place. For example, qiskit.org/documentation/stubs/… – tsgeorgios Oct 12 '20 at 13:19

The following also work for me if it is interest to you:

from qiskit import *
%matplotlib inline

circuit = QuantumCircuit(2,2)
circuit.h(0)
circuit.draw()