Python 示例：基础代码与应用

以下是一些 Python 示例：

打印'Hello World'：

print('Hello World')

计算两个数的和：

num1 = 10
num2 = 20

sum = num1 + num2

print('The sum of {0} and {1} is {2}'.format(num1, num2, sum))

判断一个数是奇数还是偶数：

num = 7

if num % 2 == 0:
    print('{0} is even'.format(num))
else:
    print('{0} is odd'.format(num))

计算一个数的阶乘：

num = 5

factorial = 1

if num < 0:
    print('Sorry, factorial does not exist for negative numbers.')
elif num == 0:
    print('The factorial of 0 is 1')
else:
    for i in range(1, num + 1):
        factorial = factorial * i
    print('The factorial of {0} is {1}'.format(num, factorial))

使用函数实现斐波那契数列：

def fibonacci(n):
    if n <= 0:
        print('Incorrect input')
    elif n == 1:
        return 0
    elif n == 2:
        return 1
    else:
        return fibonacci(n-1) + fibonacci(n-2)

print(fibonacci(10))