How to determine whether python inputs a number n to determine whether it is a prime number

How to input a number n in python to determine whether it is a prime number: 1. Use for loop and break statement, the code is [for i in range(2, k 2):if m % i == 0:break ]; 2. Use while loop and bool variables.

The operating environment of this tutorial: Windows 7 system, python version 3.9, DELL G3 computer.

How to input a number n in python to determine whether it is a prime number:

Prime number (also called prime number) means that it cannot be changed by any positive number except 1 and the number itself. A positive integer that is divisible by an integer. To determine whether a positive integer m is a prime number, you only need to determine whether m can be divisible by any positive integer from 2 to the root m. If m cannot be divided by any positive integer in this range, m is a prime number. Otherwise, m is a composite number. number.

Method one: (Using for loop and break statement)

import math
m = int(input("请输入一个整数(>1)："))
k = int(math.sqrt(m))
for i in range(2, k+2):
  if m % i == 0:
    break #可以整除，肯定不是素数，结束循环
if i == k+1: print(m, "是素数！")
else: print(m, "是合数！")

Method two: (Using while loop and bool variable)

import math
m = int(input("请输入一个整数(>1)："))
k = int(math.sqrt(m))
flag = True #假设输入的整数为素数
i = 2
while (i <= k and flag == True):
  if (m % i == 0): flag = False #可以整除，肯定不是素数，结束循环
  else: i += 1
if (flag == True): print(m, "是素数！")
else: print(m, "是合数！")

Example: Print all prime numbers between 100 and 200, output 10 per line

import math;n=0
for m in range(101,201,2):
  k = int(math.sqrt(m))
  for i in range(2,k+2):
    if m % i == 0:break
  if i == k+1:
    if n % 10 == 0:print()
    print('%d' % m,end=' ')
    n += 1

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