Welcome to our new coding practice lesson! We have an interesting problem in this unit that centers around data from a social networking app. The challenge involves processing logs from this app and extracting useful information from them. This task will leverage your skills in string manipulation, working with timestamps, and task subdivision. Let's get started!

Imagine a social networking application that allows users to form groups. Each group has a unique ID ranging from 1 up to n, the total number of groups. Interestingly, the app keeps track of when a group is created and deleted, logging all these actions in a string.

The task before us is to create a Python function named analyze_logs(). This function will take as input a string of logs and output a list of tuples representing the groups with the longest lifetime. Each tuple contains two items: the group ID and the group's lifetime. By 'lifetime,' we mean the duration from when the group was created until its deletion. If a group has been created and deleted multiple times, the lifetime is the total sum of those durations. If multiple groups have the same longest lifetime, the function should return all such groups in ascending order of their IDs.

For example, if we have a log string as follows:
"1 create 09:00, 2 create 10:00, 1 delete 12:00, 3 create 13:00, 2 delete 15:00, 3 delete 16:00",
the function will return: [(2, '05:00')].

Firstly, we import the datetime module from Python's standard library. This module provides functions and classes for working with dates and times. Once we separate the input string into individual operations, we use the datetime function to parse the timestamps contained in these operations.

Python
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1from datetime import datetime  #Importing datetime for handling timestamps
2    
3
4def analyze_logs(logs):
5    log_list = logs.split(", ")  #Break down the log string into individual logs by splitting

Next, we delve deeper into the logs. For each logged group operation in the string, we need to parse its components. These include the group ID, the type of operation (create or delete), and the time of action.

Python
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1from datetime import datetime
2
3
4def analyze_logs(logs):
5    log_list = logs.split(", ")  #Splitting the logs string into a list of logs
6    
7    for log in log_list:   
8        G_ID, action, time = log.split()  #Breaking down each log into group ID, action type, and its happening time

Now that we can identify the action performed on each group and when, it's time to process these details. We convert the group ID into an integer and the timestamp into a datetime object. If the log entry marks a 'create' action, we register the time of creation in a dictionary under the group ID. If the entry signals 'delete,' we calculate the lifetime of the group and store it in another dictionary.

Python
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1from datetime import datetime
2
3
4def analyze_logs(logs):
5    log_list = logs.split(", ")
6    time_dict = {}  #Dictionary to record the creation moment for each group
7    life_dict = {}  #Dictionary to record the lifetime for each group
8    format = '%H:%M'  #The expected timestamp format
9    
10    for log in log_list:
11        G_ID, action, time = log.split()
12        G_ID = int(G_ID)  #Casting the group's ID from string to integer
13        time = datetime.strptime(time, format)  #Casting the timestamp from string to datetime object
14        
15        if action == 'create':
16            time_dict[G_ID] = time  #If the group is created, log the creation time.
17        else:
18            if G_ID in time_dict:
19                #If the group is deleted, calculate its total lifetime and remove it from the creation records.
20                life_dict[G_ID] = life_dict.get(G_ID, datetime.strptime('00:00', format)) + (time - time_dict[G_ID])
21                del time_dict[G_ID]

After recording the lifetimes of all groups, we can compare them to determine which group or groups had the longest lifetime. Finally, we return the ID or IDs of that group or groups, sorted in ascending order, along with their lifetime.

Python
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1from datetime import datetime
2
3
4def analyze_logs(logs):
5    log_list = logs.split(", ")
6    time_dict = {}
7    life_dict = {}
8    format = '%H:%M'
9
10    for log in log_list:
11        G_ID, action, time = log.split()
12        G_ID = int(G_ID)
13        time = datetime.strptime(time, format)
14
15        if action == 'create':
16            time_dict[G_ID] = time
17        else:
18            if G_ID in time_dict:
19                life_dict[G_ID] = life_dict.get(G_ID, datetime.strptime('00:00', format)) + (time - time_dict[G_ID])
20                del time_dict[G_ID]
21
22    max_life = max(life_dict.values())  #Find the longest lifetime
23    #Build the result list where each item is a tuple of group ID and its lifetime, if it has the longest lifetime.
24    result = [(ID, str(life.hour).zfill(2) + ':' + str(life.minute).zfill(2)) for ID, life in
25              life_dict.items() if life == max_life]
26
27    return sorted(result)  #Return the list sorted in ascending order of the group IDs

Bravo! You have successfully navigated a non-trivial log analysis problem and worked with timestamped data, a real-world data type in Python. Using Python's datetime module and some clever dictionary manipulations, you transformed raw strings into meaningful data. Real-life coding often involves accurately understanding, dissecting, and analyzing data, and this unit's lesson has given you practical experience in that regard. Now, let's apply these new learnings to more practice challenges. Off to the races you go!