5 Best Ways to Convert Python Float to Time

💡 Problem Formulation: In Python, converting a float representing the number of hours since midnight into a time object is a common task. For clarity, let’s say you have a float value 3.75 which stands for 3 hours and 45 minutes past midnight. The goal is to convert this into a Python time object representing the time “03:45 AM”.

Method 1: Using datetime.timedelta and datetime.time

By leveraging the datetime.timedelta method, a duration can be created using hours as a float, which is then added to midnight represented by a datetime.time object.

Here’s an example:

import datetime

def float_to_time(hours_float):
    midnight = datetime.datetime.combine(datetime.date.today(), datetime.time.min)
    time_delta = datetime.timedelta(hours=hours_float)
    time_obj = (midnight + time_delta).time()
    return time_obj

print(float_to_time(3.75))

Output: 03:45:00

This code snippet creates a datetime.datetime object for today’s midnight and then adds a datetime.timedelta created using the float representing the hours. The time() method converts the resulting datetime into a time object.

Method 2: Using divmod to Separate Hours and Minutes

This method splits the float into whole hours and remaining minutes using divmod, which are then used to create a datetime.time object.

Here’s an example:

from datetime import time

def float_to_time(hours_float):
    hours, remainder = divmod(hours_float, 1)
    minutes = int(remainder * 60)
    return time(int(hours), minutes)

print(float_to_time(3.75))

Output: 03:45:00

The divmod function returns a tuple of hours as an integer and the fractional part. The fractional part is multiplied by 60 to convert it to minutes, which is then passed along with hours to the datetime.time constructor.

Method 3: Formatting a String Using Modulus Operator

This approach formats a string representing time by applying the modulus operator to separate hours and minutes, suitable for creating simple time strings without using datetime.

Here’s an example:

def float_to_time(hours_float):
    hours = int(hours_float) % 24
    minutes = int((hours_float % 1) * 60)
    return f"{hours:02d}:{minutes:02d}"

print(float_to_time(3.75))

Output: 03:45

The function calculates hours and minutes separately using modulus and integer operations. It then returns the time formatted as a zero-padded string.

Method 4: Using datetime.strptime to Parse a String Representation

This method involves converting the float to a formatted string and then parsing it with datetime.strptime to create a datetime.time object.

Here’s an example:

from datetime import datetime

def float_to_time(hours_float):
    hours = int(hours_float)
    minutes = int((hours_float - hours) * 60)
    time_str = f"{hours:02d}:{minutes:02d}"
    return datetime.strptime(time_str, '%H:%M').time()

print(float_to_time(3.75))

Output: 03:45:00

First, the function constructs a time string from the float. It then uses datetime.strptime to transform the string into a datetime.time object.

Bonus One-Liner Method 5: Using a Lambda Function and Map

A concise way to achieve the conversion using a lambda function with map to execute operations over hours and minutes simultaneously.

Here’s an example:

from datetime import time

float_to_time = lambda hours_float: time(*map(int, divmod(hours_float * 60, 60)))
print(float_to_time(3.75))

Output: 03:45:00

This single-line lambda function multiplies the hours float by 60 to get total minutes, uses divmod to split it into hours and minutes, and then unpacks them into the datetime.time constructor.

Summary/Discussion

• Method 1: Using datetime.timedelta and datetime.time. Strengths: It provides a standard and reliable way to convert times. Weaknesses: Slightly more complex than other methods.
• Method 2: Using divmod to separate hours and minutes. Strengths: Simple and easy to understand. Weaknesses: Does not manage scenarios beyond 24 hours.
• Method 3: Formatting a string using the modulus operator. Strengths: Quick and efficient for creating string representations of time. Weaknesses: Does not create a time object.
• Method 4: Using datetime.strptime to parse a string representation. Strengths: Competent at handling different time formats. Weaknesses: Involves redundant conversion to string before parsing.
• Bonus One-Liner Method 5: Using a lambda function and the map. Strengths: Compact and one line of code. Weaknesses: Less readable for those unfamiliar with lambda and map functions.