df.loc question

[Led_Zeppelin]

In the following code which as you can see there is one dataframe.

q = df.loc[df2['machine_status']==0]['sensor_06']
p = df.loc[df2['machine_status']==1]['sensor_06'][:q.shape[0]]

pp = sm.ProbPlot(p)
pq = sm.ProbPlot(q)
qqplot_2samples(pp,pq)
plt.title("Q-Q plot of sensor_6 for machine_statuts")
plt.show()

I take the term to be a complete function when working on a dataframe. In this case data it is working on is df2. I know that they could use more meaningful names but bear with me. This works as shown in the attachment.

But when I use the following code which is very similar to the above code, I get an error.

The code is:

Output:
NameError                                 Traceback (most recent call last)
Input In [7], in <cell line: 1>()
----> 1 q = df.loc[df2['machine_status']==0]['time_period']
      2 p = df.loc[df2['machine_status']==1]['time_period'][:q.shape[0]]
      4 pq = np.sum(p * np.log(p/q))

NameError: name 'df' is not defined

I am using the function in the same program in the same environment. It likes the first but does not like the second.

I need to know what to put in the fix this condition on the second function.

Respectfully,

LZ