字典生成算法的nodejs和python实现比较

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两者都用到了map，即数组映射，典型的数学函数思维。时间上python稍快，8核电脑分别为6-7秒，7-8秒。l(n)为字典字符长度，如l(4)为4位base里的字符遍历。
1、python源码

1. import time
   
2. base=list("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
   
3. init=base
   
4. i=1
   
5. def rd(x):
   
6.     return ",".join(list(map(lambda a:",".join(list(map(lambda b:a+""+b,base))),x))).split(",")
   
7. 
   
8. def l(n):
   
9.     global i,init
   
10.     td=time.time()
    
11.     while i<n:
    
12.         i =i+1
    
13.         init=rd(init)
    
14.     i=0
    
15.     print(time.time()-td)
    
16.     return init
    
17. d=time.time()
    
18. fs=open("d:\\tmp\\6.txt","w")
    
19. fs.write(" ".join(l(4)))
    
20. fs.close()
    
21. print (time.time()-d)
    

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2、nodejs源码：

1. function rd(x){x=x||base;return x.map(function(a){ return base.map(function(b){ return a+b}).join(",")}).join(",").split(",")}
   
2. base="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".split("");
   
3. init=base;
   
4. i=0
   
5. function l(n){
   
6. d=new Date().getTime()
   
7. while (++i<n) {init=rd(init)}
   
8. i=0
   
9. console.log(new Date().getTime()-d)
   
10. return init
    
11. }
    
12. 
    
13. fs=require("fs")
    
14. d=new Date().getTime()
    
15. fs.writeFile("d:\\tmp\\4.txt",l(4).join(" "),"utf-8",function(e,r){
    
16. console.log(new Date().getTime()-d)})
    

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