输入一个数，判断是不是素数_输入一个数判断是否为素数

题目34：输入一个数，判断是不是素数

封装方法：

def  is_prime(num):
    if  not  isinstance(num,int):
        return False
    for i in range(2,num):
        if num%i == 0:
            return False
    return True

print(is_prime(13))
print(is_prime(101))
print(is_prime(10))
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不封装方法：

input_num =int( input("请输入数字："))
for  i  in range(2,input_num):
    if  input_num % i ==0:
        print(input_num,"is not a prime num!")
        break
else:
print(input_num,"is a  prime number!")
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input_num =int( input("请输入数字："))
if   input_num==1:
    print(input_num,"is  not a  prime number!")
if   input_num==2:
    print(input_num,"is   a  prime number!")
for  i  in range(2,input_num):
    if  input_num % i ==0:
        print(input_num,"is not a prime num!")
        break
    if i == input_num-1:
        print(input_num,"is a  prime number!")
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用math.sqrt方法来判断素数：

import math
def   is_prime(num):
    if  not isinstance(num,int):
        return False
    for i in range(2,int(math.sqrt(num)+1)):
        if num%i == 0:
            return False
    return True

print(is_prime(13))
print(is_prime(101))
print(is_prime(10))
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用math.sqrt方法来判断素数：

import math
def   is_prime(num):
   
    if  not isinstance(num,int):
        return False
    if num ==1:
        return False
    if num == 2:
        return True
    for i in range(2,int(math.sqrt(num)+1)):
        if num%i == 0:
            return False
    return True
result = 0
for i in range(1,101):
    if   is_prime(i):
        result+=i
        print(i)  
print(result)
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