24-hour time in Python

Converting 12-hour time format to 24-hour format is a common task in Python programming. The 12-hour format uses AM/PM suffixes, while 24-hour format uses hours from 00 to 23.

So, if the input is like "08:40pm", then the output will be "20:40".

Algorithm

To solve this, we will follow these steps ?

• Extract hour from the time string and apply modulo 12 to handle 12 AM/PM cases

• Extract minutes from the time string

• If the suffix is 'p' (PM), add 12 to the hour

• Return the formatted 24-hour time

Example

Let us see the following implementation to get better understanding ?

class Solution:
    def solve(self, s):
        hour = int(s[:2]) % 12
        minutes = int(s[3:5])
        if s[5] == 'p':
            hour += 12
        return "{:02}:{:02}".format(hour, minutes)

ob = Solution()
print(ob.solve("08:40pm"))
print(ob.solve("12:30am"))
print(ob.solve("12:15pm"))
print(ob.solve("01:45am"))

20:40
00:30
12:15
01:45

Using datetime Module

Python's datetime module provides a more robust approach for time conversion ?

from datetime import datetime

def convert_to_24hour(time_str):
    # Parse 12-hour format and convert to 24-hour format
    time_obj = datetime.strptime(time_str, "%I:%M%p")
    return time_obj.strftime("%H:%M")

# Test with different time formats
times = ["08:40pm", "12:30am", "12:15pm", "01:45am"]

for time in times:
    result = convert_to_24hour(time)
    print(f"{time} ? {result}")

08:40pm ? 20:40
12:30am ? 00:30
12:15pm ? 12:15
01:45am ? 01:45

Comparison

Conclusion

Both methods effectively convert 12-hour to 24-hour format. Use manual parsing for simple cases or the datetime module for more robust time handling with proper error checking.