Python函数的使用案例

发布时间：2023-06-15 22:07:36

1.计算器应用程序

Python函数可以用来创建一个包含基本运算（加、减、乘、除）的计算器应用程序。其中，每个计算操作都由一个单独的函数实现，例如add()、subtract()、multiply()和divide()函数。

def add(a, b):

return a + b

def subtract(a, b):

return a - b

def multiply(a, b):

return a * b

def divide(a, b):

if b == 0:

return "Error: division by zero!"

else:

return a / b

print("Select an operation:")

print("1. Add")

print("2. Subtract")

print("3. Multiply")

print("4. Divide")

choice = input("Enter choice (1/2/3/4): ")

num1 = float(input("Enter first number: "))

num2 = float(input("Enter second number: "))

if choice == '1':

print(num1, "+", num2, "=", add(num1, num2))

elif choice == '2':

print(num1, "-", num2, "=", subtract(num1, num2))

elif choice == '3':

print(num1, "*", num2, "=", multiply(num1, num2))

elif choice == '4':

print(num1, "/", num2, "=", divide(num1, num2))

else:

print("Invalid input")

2.密码生成器

Python函数可以用来生成随机密码。特别是，using_password()函数可以从一个包含所有可能字符的字符串中随机选择N个字符来生成一个密码。用户可以指定密码长度和包含的字符类型。

import random

def using_password(length, capital, small, numbers, symbols):

password_dict = {}

password = ''

capital_letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

small_letters = 'abcdefghijklmnopqrstuvwxyz'

digits = '0123456789'

symbols_list = '!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~'

if capital == 'yes':

password_dict['capital_letters'] = capital_letters

if small == 'yes':

password_dict['small_letters'] = small_letters

if numbers == 'yes':

password_dict['digits'] = digits

if symbols == 'yes':

password_dict['symbols_list'] = symbols_list

password_items = password_dict.items()

password_list = list(password_items)

password_int = length-len(password_list)

for i in range(password_int):

chosen_dict = random.choice(password_list)

password += random.choice(chosen_dict[1])

password += ''.join(random.sample(capital_letters, 1))

password += ''.join(random.sample(small_letters, 1))

password += ''.join(random.sample(digits, 1))

password += ''.join(random.sample(symbols_list, 1))

password_list = list(password)

random.shuffle(password_list)

password = ''.join(password_list)

return password

3.矩阵计算器

Python函数可以用来进行矩阵计算。特别是，matrix_addition()函数和matrix_multiplication()函数可以分别执行矩阵加法和矩阵乘法。

def matrix_addition(matrix1, matrix2):

result = []

for i in range(len(matrix1)):

row = []

for j in range(len(matrix1[0])):

row.append(matrix1[i][j] + matrix2[i][j])

result.append(row)

return result

def matrix_multiplication(matrix1, matrix2):

result = []

for i in range(len(matrix1)):

row = []

for j in range(len(matrix2[0])):

sum = 0

for k in range(len(matrix2)):

sum += matrix1[i][k] * matrix2[k][j]

row.append(sum)

result.append(row)

return result

matrix1 = [[1, 2], [3, 4]]

matrix2 = [[5, 6], [7, 8]]

print("Matrix addition: ", matrix_addition(matrix1, matrix2))

print("Matrix multiplication: ", matrix_multiplication(matrix1, matrix2))

4.文件管理器

Python函数可以用来创建一个文件管理器应用程序。其中，create_file()函数可以创建一个新的文件；read_file()函数可以读取一个文件的内容；write_file()函数可以写入文件的内容；delete_file()函数可以删除一个文件。

import os

def create_file(file_name, contents):

with open(file_name, 'w') as file_object:

file_object.write(contents)

def read_file(file_name):

with open(file_name) as file_object:

contents = file_object.read()

print(contents)

def write_file(file_name, contents):

with open(file_name, 'a') as file_object:

file_object.write(contents)

def delete_file(file_name):

os.remove(file_name)

file_name = 'test.txt'

contents = 'This is a test file.'

create_file(file_name, contents)

read_file(file_name)

new_contents = 'This is the updated contents.'

write_file(file_name, new_contents)

read_file(file_name)

delete_file(file_name)

5.天气应用程序

Python函数可以用来创建一个天气应用程序。特别是，get_city_weather()函数可以通过API获取指定城市的当前天气状况；parse_weather()函数可以解析API响应中的关键数据；display_weather()函数可以向用户显示解析后的天气数据。

import requests

def get_city_weather(city_name, api_key):

url = f'http://api.openweathermap.org/data/2.5/weather?q={city_name}&appid={api_key}'

response = requests.get(url)

return response.json()

def parse_weather(response):

main_result = response['main']

temperature = main_result['temp']

pressure = main_result['pressure']

humidity = main_result['humidity']

description_result = response['weather']

description = description_result[0]['description']

return temperature, pressure, humidity, description

def display_weather(city_name, temperature, pressure, humidity, description):

print(f"The current weather in {city_name} is {description}, with a temperature of {temperature} Kelvin, a pressure of {pressure} hPa, and a humidity of {humidity}%.")

city_name = 'Beijing'

api_key = 'insert_your_api_key_here'

response = get_city_weather(city_name, api_key)

temperature, pressure, humidity, description = parse_weather(response)

display_weather(city_name, temperature, pressure, humidity, description)

总结

Python函数可以应用于许多不同类型的任务和应用程序中，包括计算、安全、数据处理、文件管理和API交互等。上述五个使用案例分别展示了不同类型应用程序中使用Python函数的示例。不仅如此，Python函数可以大量减少代码重复度，并有助于提高应用程序的可读性和易于维护性。