How do I add dictionary individual key values together?

Question

I have a dictionary containing people and their duration of completing a task. I wish too add their individual times.

office_time_dict = {
    "john": ["0:00:30", "0:02:04", "0:00:16"],
    "bryan": ["0:00:30", "0:02:04", "0:00:16"],
    "mike": ["0:00:30", "0:02:04", "0:00:16"],
}
total_time = 0

for k, v in office_time_dict.items():
    office = office_time_dict[k]
    for time in office:
        timeparts = [int(s) for s in time.split(":")]
        total_time += (timeparts[0] * 60 + timeparts[1]) * 60 + timeparts[2]
    total_time, sec = divmod(total_time, 60)
    hr, min = divmod(total_time, 60)
    print("%d:%02d:%02d" % (hr, min, sec))

current output: 0:02:50, 0:02:52, 0:02:52

Confused as to what I am doing wrong since all outputs should be the same for john, bryan, and mike but bryan and mike are off by 2 seconds

Answer 1

Try this:

office_time_dict = {'john': ['0:00:30', '0:02:04','0:00:16'], 'bryan': ['0:00:30', 
                   '0:02:04','0:00:16'], 'mike' : ['0:00:30', '0:02:04','0:00:16']}

for person in office_time_dict:
    office = office_time_dict[person]
    total_time = 0 # re-initialise total_time for each person inside loop
    for time in office:
        timeparts = [int(s) for s in time.split(':')]
        total_time += (timeparts[0] * 60 + timeparts[1]) * 60 + timeparts[2]
    total_time, sec = divmod(total_time, 60)
    hr, min = divmod(total_time, 60)
    print('%d:%02d:%02d' % (hr, min, sec))

Answer 2

You'll have a better time if you break out the HH:MM:SS-to-seconds (and vice versa) code to functions of their own:

# Convert a h:m:s string to seconds
def hms_to_sec(hms):
    h, m, s = [int(part, 10) for part in hms.split(":")]
    return h * 60 * 60 + m * 60 + s


# Convert seconds to h:m:s
def sec_to_hms(s):
    hm, s = divmod(s, 60)
    h, m = divmod(hm, 60)
    return "%02d:%02d:%02d" % (h, m, s)


# Source data (slightly modified from question so the guys have different times)
office_time_dict = {
    "john": ["0:00:30", "0:02:04", "0:00:16"],
    "bryan": ["0:00:20", "0:03:04", "0:00:16"],
    "mike": ["0:00:10", "0:04:04", "0:00:16"],
}

# Convert each person's time to seconds and sum up
total_times_sec = {
    person: sum(hms_to_sec(time) for time in times)
    for (person, times) in office_time_dict.items()
}

# Convert the summed seconds back to H:M:S
total_times_hms = {
    person: sec_to_hms(sec) for (person, sec) in total_times_sec.items()
}

# Sum the seconds and convert back to H:M:S
grand_total_hms = sec_to_hms(sum(total_times_sec.values()))

print(total_times_hms)
print(grand_total_hms)

This prints out

{'john': '00:02:50', 'bryan': '00:03:40', 'mike': '00:04:30'}
00:11:00

Answer 3

You have the variable total_time initialized only once, before your main loop:

total_time = 0

After every iteration of your main loop the value of total_time in not 0 , but 2 .
This value is then added in the command

total_time += (timeparts[0] * 60 + timeparts[1]) * 60 + timeparts[2]

---

How to correct it:

Move the initialization into your main loop:

for k, v in office_time_dict.items():
    total_time = 0

Answer 4

You just need to move the initialization of total_time inside the loop. You can also use the value returned by the items() method instead of access the dictionary by key.

office_time_dict = {'john': ['0:00:30', '0:02:04','0:00:16'],
                    'bryan': ['0:00:30', '0:02:04','0:00:16'],
                    'mike' : ['0:00:30', '0:02:04','0:00:16']}
 
for k, v in office_time_dict.items():
    total_time = 0
    for time in v:
        timeparts = [int(s) for s in time.split(':')]
        total_time += (timeparts[0] * 60 + timeparts[1]) * 60 + timeparts[2]
    total_time, sec = divmod(total_time, 60)
    hr, minutes = divmod(total_time, 60)
    print('%d:%02d:%02d' % (hr, minutes, sec))