Master Python Functions and Time Utilities: From Basics to Real-World Code

1. Function Overview

In Python, a function groups specific code into a reusable unit that can be invoked whenever needed.

2. Function Definition and Invocation

A function definition creates a tool that performs a particular task.

def test():
    print('----嘻嘻----')
    print('----这是我的第一个函数----')

Defining a function alone does not execute it; it must be called.

# Define a function
def test():
    print('----嘻嘻----')
    print('----这是我的第一个函数----')

# Call the function
test()

Result:

Python’s rich set of built‑in functions contributes to its popularity among developers.

Time Functions

Debugging often requires timestamp output, which is provided by time‑related functions.

1. Get current timestamp: time.time()

import time  # import time module
currentTime = time.time()
print("当前时间戳为:", currentTime)

Result:

2. Get local time tuple: time.localtime(time.time())

import time
localtime = time.localtime(time.time())
print("本地时间为 :", localtime)

Result:

import time
localtime = time.asctime(time.localtime(time.time()))
print("本地时间为 :", localtime)

Result:

Extended (datetime module)

1. Date formatting: datetime → string

import datetime
now = datetime.datetime.now()
now.strftime('%Y-%m-%d %H:%M:%S')

2. String → datetime

import datetime
t_str = '2019-04-07 16:11:21'
d = datetime.datetime.strptime(t_str, '%Y-%m-%d %H:%M:%S')
print(d)

Result:

strptime is a static method of the datetime class.

3. Date comparison using timedelta

The timedelta class represents a time interval and supports arithmetic.

import datetime
datetime.timedelta(days=0, seconds=0, microseconds=0, milliseconds=0,
                   minutes=0, hours=0, weeks=0)

All parameters default to 0; you can access attributes such as days or seconds.

import datetime
year = datetime.timedelta(days=365)
t_years = year * 10
new_years = t_years - year
print(t_years)
print(new_years)

Result:

date, time, and datetime classes also support addition and subtraction with timedelta, enabling convenient operations.

datetime1 = datetime2 + timedelta
timedelta = datetime1 - datetime2

Calendar Functions

import calendar
dar = calendar.month(2016, 8)
print("2016年8月份的日历:")
print(dar)

Result:

Random Number Functions

import random
a = random.uniform(1, 5)
print("a =", a)

b = random.randint(10, 50)
print("b =", b)

c = random.randrange(0, 51, 2)
print("c =", c)

Result:

3. Summary

This article detailed Python function definitions and calls, introduced common time‑related functions, and provided practical code examples to help readers better understand and apply functions in Python programming.