How to calculate hours between two differnet time in the 12 hour in python and also divide the hours into three parts (timesheet hours calculate)

Question

Assume all times are between 6:00 PM and 6:00 AM. The input of time would be like

7:00    5:30     # 7:00 PM to 5:30 AM
6:00    1:45     # 6:00 PM to 1:45 AM

Divide the hours into three periods: the hours before 9:00 PM, hours between between 9:00 PM and midnight, and hours after midnight

My expected output

[2.0, 3.0, 5.5]
[3.0, 3.0, 1.75]

What I have:

import datetime as dt

start="9:00"
end="00:00"
start_dt = dt.datetime.strptime(start, '%H:%M')
end_dt = dt.datetime.strptime(end, '%H:%M')

hours_added = dt.datetime.strptime("12:00", '%H:%M')
diff = (end_dt - start_dt) 
if end < start:
    diff = diff.seconds/60/60 - 12.0
print(diff) # It prints 3.0

More other inputs

8:00   10:00
9:00    11:30
9:30    1:00
6:00    9:00
7:15    8:15
7:00    5:30
6:00    1:45
9:30    1:00
7:00    9:00
1:15    3:15
7:00    3:30
9:00    1:45

Answer 1

This was more challenging than it first appears - took me a while to figure out. The difficult part is dealing with the fact that the end time may be in the next day. I dealt with this by specifying the date in the datetime objects to make the datetime arithmetic simpler later on. I used 01/01/2020 for the first day and 02/01/2020 for the second day (dd/mm/YYYY format), but these could be any arbitrary dates.

I'm afraid I've run out of time to talk step-by-step through the code but hopefully it's descriptive enough to follow. Let me know if you have any questions!

import datetime as dt

start="06:00"
end="01:45"
# Parse the times so that you can get the hour and minute
start_dt = dt.datetime.strptime(start, '%H:%M')
end_dt = dt.datetime.strptime(end, '%H:%M')

# === CONVERT TO 24-HOUR CLOCK ===

# If the start time is later than 06:00, convert to PM.
if start_dt.hour < 6:
    start_dt = dt.datetime.strptime(f'02/01/2020 {start}AM', '%d/%m/%Y %I:%M%p')
else:
    start_dt = dt.datetime.strptime(f'01/01/2020 {start}PM', '%d/%m/%Y %I:%M%p')
# Do the same for end time (you could wrap this in a function later
# to avoid repetition)
if end_dt.hour < 6:
    end_dt = dt.datetime.strptime(f'02/01/2020 {end}AM', '%d/%m/%Y %I:%M%p')
else:
    end_dt = dt.datetime.strptime(f'01/01/2020 {end}PM', '%d/%m/%Y %I:%M%p')

# === DEFINE KEY TIME POINTS ===

nine_pm = dt.datetime.strptime(f'01/01/2020 09:00PM', '%d/%m/%Y %I:%M%p')
midnight = dt.datetime.strptime(f'02/01/2020 12:00AM', '%d/%m/%Y %I:%M%p')
zero_hours = dt.timedelta(hours=0)

# === DO THE MATH ===

total_hours = end_dt - start_dt

if total_hours > zero_hours:
    if end_dt > nine_pm:
        hours_before_nine = total_hours - (end_dt - nine_pm)
        total_hours = total_hours - hours_before_nine
    else:
        hours_before_nine = total_hours
        total_hours = zero_hours
else:
    hours_before_nine = zero_hours

if total_hours > zero_hours:
    if end_dt > midnight:
        hours_between_nine_and_midnight = total_hours - (end_dt - midnight)
        total_hours = total_hours - hours_between_nine_and_midnight
    else:
        hours_between_nine_and_midnight = total_hours
        total_hours = zero_hours
else:
    hours_between_nine_and_midnight = zero_hours

if total_hours > zero_hours:
    hours_after_midnight = total_hours
else:
    hours_after_midnight = zero_hours

# === PRINT THE RESULT ===

hours_before_nine = hours_before_nine.seconds/60/60
hours_between_nine_and_midnight = hours_between_nine_and_midnight.seconds/60/60
hours_after_midnight = hours_after_midnight.seconds/60/60

print([hours_before_nine, hours_between_nine_and_midnight, hours_after_midnight])

Answer 2

def calc_hours (time1,time2):
  import datetime as dt
  nl = []
  start= time1
  end= time2

  start_hour = int(start.split(":")[0])
  start_min = int(start.split(":")[1])

  end_hour = int(end.split(":")[0])
  end_min = int(end.split(":")[1])

  if end_hour < start_hour:
    end_hour += 12

  start_dt = dt.datetime.strptime(start, '%H:%M')
  end_dt = dt.datetime.strptime(end, '%H:%M')


  ninepm = dt.datetime.strptime("09:00",'%H:%M')
  midnight = dt.datetime.strptime("12:00",'%H:%M')
  hours_added = dt.datetime.strptime("12:00", '%H:%M')
  diff = (end_dt - start_dt)

  if start_hour + start_min/60 < 9:
    if end_hour <= 9:
      diff = diff.seconds/60/60
      nl.append(diff)
    elif end_hour <= 12:
      nl.append((ninepm - start_dt).seconds/60/60)
      if end_hour == 12:
        nl.append(((end_dt + dt.timedelta(hours=12))-ninepm).seconds/60/60)
      elif end_hour < 12:
        nl.append((end_dt-ninepm).seconds/60/60)
    elif end_hour > 12:
      nl.append((ninepm - start_dt).seconds/60/60)
      nl.append((midnight-ninepm).seconds/60/60)
      nl.append(((end_dt + dt.timedelta(hours=12))-midnight).seconds/60/60)

  elif start_hour + start_min/60 >= 9:
    if end_hour <= 12:
      if end_hour < 12:
        diff = diff.seconds/60/60
        nl.append(diff)
      elif end_hour == 12:
        nl.append(((end_dt + dt.timedelta(hours=12))-start_dt).seconds/60/60)
    else :
      nl.append((midnight-start_dt).seconds/60/60)
      nl.append(((end_dt + dt.timedelta(hours=12))-midnight).seconds/60/60)
      
  elif start_hour + start_min/60 > 12:
    nl.append(diff)
    
  return nl