Question

#Enter an integer
num = int(input("Enter a number: "))

#Prime number is a positive integer that is evenly divisible by 1 and itself
#Zero and one shouldn't be prime numbers

#Use for loop in the range of 2 as the first prime to any integer num
#If else statements: If integer num is divisible by any integer between
#2 and itself the integer num isn't a prime number
#or else the integer is a prime number

if num < 2:
    print(num, "isn't a prime number")

for x in range(2, num):
    if num % x == 0:
        print(num, "isn't a prime number")
        break
else:
    print(num, "is a prime number")

观察 -

当我单独输入整数0和整数1时，我得到的输出是：

0 isn't a prime number 
0 is a prim number
1 isn't a prime number
1 is a prime number

请记住这是if循环之前的for语句。有了它，整个程序输出每隔一个正确的整数。但仍然是整数0和1：

输出：

0 is a prime number
1 is a prime number

Answer 1

检查num < 2时，您不会返回。你可以改为：

if num < 2:
    print(num, "isn't a prime number")
    return

假设你在一个函数中。否则，您可以使用else：

if num < 2:
    print(num, "isn't a prime number")
else:
    for x in range(2, num):
        if num % x == 0:
            print(num, "isn't a prime number")
            break
    else:
        print(num, "is a prime number")

Answer 2

一旦确认它低于2：

，就需要停止

仅使用以下一个 ...

如果您正在循环，则继续下一次迭代：

if num < 2:
    print(num, "isn't a prime number")
    continue

如果你在一个函数中，并想要返回一个值：

if num < 2:
    print(num, "isn't a prime number")
    return False

如果您没有循环或在函数中，并且想要终止该程序：

if num < 2:
    print(num, "isn't a prime number")
    sys.exit()

Answer 3

在初始IF条件之后，您没有return语句或else子句。

也只是一个快速提示，无需检查每个整数的模数。我相信只有一半的数字是必要的。我编程了一个素数算法已经有一段时间了。

Python - 识别整数是否为素数？输出打印素数而不是素数

3 个答案: