Python enables efficient solution of prime code instances

Prime numbers are often needed in programming.

As an example of learning Python, here is a program that efficiently solves a range of primes without using division or modulo operations.

#coding: Utf-8    #设置python文件的编码为utf-8, so you can write Chinese note def primerange (n):  myarray=[1 for x in range (n+1)] # #列表解析, Generate a list of length (n+1) with each value 1  myarray[0]=0  myarray[1]=0 startpos=2 while  startpos <= N:    if myarray[ Startpos]==1:      key=2      resultpos = startpos * Key #可知startPos的整数倍都不是素数, set the integer multiples of startpos to 0 for non-prime while      Resultpos <= N:        myarray[resultpos] =0        key + = 1        resultpos = startpos *key    startpos + = 1  Resultlist=[]  # #将最终的素数保存在resultList列表返回  startpos=0 while  startpos <= N:    if Myarray[startpos ] = = 1:      resultlist.append (startpos)    startpos + = 1  return resultlistnumstring=raw_input ("input the Range (>3): ") Numint=int (numstring) if Numint <= 3:  print" The number need to be greater than 3 "else:  PrimeR Esult=primerange (numint)  print "The Result is:", Primeresult

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