This code cell converts the data from the file into a list of integer values, and stores the result in variable Answer$1.$ It also prints Answer$1$ so you can see the result. WebCAT will grade the contents of Answer$1.$

But, there is a bug. First, run the entire notebook $($click "Kernel $|$ Restart and Run All" or the FastForward button on the toolbar$).$ Notice the printed results here are incorrect, displaying an empty list. Why?

Now immediately run this code cell again $($click the cell, then shift$-$enter$).$ Magically the correct Answer$1$ is shown containing several integer values. Why did it change? Hint: See the code in Problem $2.$ Python maintains state, despite out of order interactive execution, code edits, etc.

So you might think that the result is now correct and can be submitted to WebCAT. No$,$ WebCAT will run the code cells in order from scratch, and produce the wrong result in Answer$1.$This code cell converts the data from the file into a list of integer values, and stores the result in variable Answer$1.$ It also prints Answer$1$ so you can see the result. WebCAT will grade the contents of Answer$1.$

But, there is a bug. First, run the entire notebook $($click "Kernel $|$ Restart and Run All" or the FastForward button on the toolbar$).$ Notice the printed results here are incorrect, displaying an empty list. Why?

Now immediately run this code cell again $($click the cell, then shift$-$enter$).$ Magically the correct Answer$1$ is shown containing several integer values. Why did it change? Hint: See the code in Problem $2.$ Python maintains state, despite out of order interactive execution, code edits, etc.

So you might think that the result is now correct and can be submitted to WebCAT. No$,$ WebCAT will run the code cells in order from scratch, and produce the wrong result in Answer$1.$