Python脚本查找第n个质数

本文介绍了Python脚本查找第n个质数的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我是Python的新手，我想我会尝试通过编写一个函数来找到第n个素数来学习一些技巧，但是我无法使我的代码正常工作.毫无疑问，这是由于我遗漏了一些基本知识，但是我很感谢您在发现错误之处方面的帮助！

I'm new to Python and I thought I'd try to learn the ropes a bit by writing a function to find the nth prime number, however I can't get my code to work properly. No doubt this is due to me missing something fundamental, but I'd appreciate your help in finding where it went wrong!

c=2 n=input("Which prime would you like? ") n=int(n) a=[] l=len(a) while l<=n: if c==2: a.append(c) elif (c % 2 ==0): #c is even break elif (c % 2 !=0): #c is odd if c<7: a.append(c) elif c >=7: for i in range(3,int((c+1)/2)): if (c % i ==0): break else: a.append(c) else: c+=1 a[n]

谢谢！ 安德鲁

推荐答案

这可以是一个开始.这将检查数字N是否可被2至int(sqrt(N)) + 1的所有数字整除，其中int函数将截断N的平方根.如果列表中的所有成员，python中的all()函数将返回True满足一些条件(此处不为零).您应该设置一个上限，因为对于很大的n来说这不是很有效.我把它留给你.

This can be a start. This checks whether the number N is divisible by all numbers from 2 to int(sqrt(N)) + 1, where the int function truncates the square root of N. The all() function in python returns True if all members of a list satisfy some condition (here not zero). You should set an upper bound as this is not very efficient for really large n. I'll leave that to you.

def nthprime(n): import math start = 2 count = 0 while True: if all([start % i for i in range(2, int(math.sqrt(start)) + 1)]) != 0: count += 1 if count == n: return start start += 1 In [91]: nthprime(50) Out[91]: 229 In [92]: nthprime(100) Out[92]: 541

使用此进行了测试.