Python 程式檢查數字是否為素數
一個素數是一個大於 1 的自然數,它不是兩個較小自然數的乘積。任何大於 1 且只有兩個因數(即 1 和它本身)的整數都稱為素數。
假設我們的輸入如下所示:
7
輸出應如下所示:
Prime Number
檢查數字是否為素數
讓我們使用for 迴圈檢查一個數字是否為素數:
示例
# Number to be checked for prime n = 5 # Check if the number is greater than 1 if n > 1: for i in range(2, int(n/2)+1): if (n % i) == 0: print(num, "is not a prime number") break else: print(n, "is a prime number") # If the number is less than 1, its also not a prime number. else: print(n, "is not a prime number")
輸出
5 is a prime number
使用 sqrt() 檢查數字是否為素數
讓我們使用sqrt() 方法檢查一個數字是否為素數:
示例
from math import sqrt # Number to be checked for prime n = 9 flag = 0 if(n > 1): for k in range(2, int(sqrt(n)) + 1): if (n % k == 0): flag = 1 break if (flag == 0): print(n," is a Prime Number!") else: print(n," is Not a Prime Number!") else: print(n," is Not a Prime Number!")
輸出
9 is Not a Prime Number!
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