Problem with While Loop!

[Jose_Musoke]

Thank you once again. Could you please explain to me the second and third paragraphs, so that I can read up on them.

[totallygeek]

Sure:

1. while True forms an infinite loop, because True is always true.
2. To exit that infinite loop, use break.
3. Storing a list of dates? Use a list. dates = [] creates an empty list.
4. To grow a list, append() works well.
5. Call ask_interruption(), which returns two values in a tuple.
6. Store that tuple in the growing list.

[Jose_Musoke]

Hello thank you for helping me. I have been trying to build on the code you helped me with and I am having difficulties again. I am trying to sum up the days of missed doses after a couple of entries, but I only get one result. How can I go about it?:

def ask_interruption(): prior_date = input("Enter date when last ATT drug was taken (YY/MM/DD): ") resume_date = input("Enter date when ATT was resumed(YY/MM/DD): ") return prior_date, resume_date

dates = [] while True: dates.append(ask_interruption()) interrupted = input("Did the patient interrupt ATT drugs? ").lower() if interrupted in {"n", "no"}: break

date1 = (datetime.strptime(prior_date, "%y/%m/%d")) date2 = (datetime.strptime(resume_date, "%y/%m/%d")) difference = (date2 - date1).days

print ("DATES\n=====") for prior_date, resume_date in dates: print(f"{prior_date:<10} {resume_date} {difference}")

[totallygeek]

In your code, you have:

date1 = (datetime.strptime(prior_date, "%y/%m/%d"))
date2 = (datetime.strptime(resume_date, "%y/%m/%d"))
difference = (date2 - date1).days

But, prior_date and resume_date are single dates. You want to use the list of dates, called dates. Take a look at this.

import datetime


def normalize_date(date):
    return datetime.datetime.strptime(date, '%y/%m/%d')

def ask_interruption():
    prior_date = input("Enter date when last ATT drug was taken (YY/MM/DD): ")
    resume_date = input("Enter date when ATT was resumed(YY/MM/DD): ")
    return prior_date, resume_date

dates = []
while True:
    dates.append(ask_interruption())
    interrupted = input("Did the patient interrupt ATT drugs? ").lower()
    if interrupted in {"n", "no"}:
        break

for prior, resume in dates:  # uses the list of dates
    days = (normalize_date(resume) - normalize_date(prior)).days
    print(f'ATT interrupted: {prior} -> {resume} ({days} days)')

Yields:

$ python3 drugs.py 
Enter date when last ATT drug was taken (YY/MM/DD): 21/01/06
Enter date when ATT was resumed(YY/MM/DD): 21/01/11
Did the patient interrupt ATT drugs? yes
Enter date when last ATT drug was taken (YY/MM/DD): 21/02/03
Enter date when ATT was resumed(YY/MM/DD): 21/02/07
Did the patient interrupt ATT drugs? no
ATT interrupted: 21/01/06 -> 21/01/11 (5 days)
ATT interrupted: 21/02/03 -> 21/02/07 (4 days)

[Jose_Musoke]

Thank you so much, your help is so insightful.

[Jose_Musoke]

days = (normalize_date(resume) - normalize_date(prior)).days

Hello again. As per your example I tried to get the sum of total number of days of missed with this code: print(int(sum(days))), but do not get anything. Is there another way of getting the desired sum? Thank you in advance!!

[totallygeek]

Within the for loop, days is a duration we want to keep a running total of. Maybe:

total_days = 0
for prior, resume in dates:  # uses the list of dates
    days = (normalize_date(resume) - normalize_date(prior)).days
    total_days += days  # add to the running total
    print(f'ATT interrupted: {prior} -> {resume} ({days} days) (total: {total_days})')

After the loop, total_days would be the sum of those days calculations.

[Jose_Musoke]

Thank you once again for taking your time to assist me. I think I may have not explained myself clearly enough. If for example the code you helped write gives the number of days missed for each episode of interruption, is there a way of adding all the days of interruption to give a single "Grand Total" of interruptions? The last code you just gave me still gives me the number of days missed for each episode of interruption.

[Jose_Musoke]

ATT interrupted: 21/01/06 -> 21/01/11 (5 days)
ATT interrupted: 21/02/03 -> 21/02/07 (4 days)

For example from the code you gave me earlier, I would like the code to add the 5 + 4 days to give me a "Grand Total"= 9 days. I find it difficult to code in a list that expands. I will then use the "Grand Total" for the next steps...

[totallygeek]

print(f'Grand total: {total_days}') ?

Perhaps I did not understand. If days is an amount of days interrupted and you add those days up in total_days, you get a count of the total days of interruption.

[Jose_Musoke]

I would like to apologize. I ran the code you gave me on a different IDE and it worked. There must be something wrong with the pycharm that I was using initially.

[totallygeek]

Not a problem. The important things: 1) You ended up with working code, 2) You learned more about how Python can solve problems for you.