concatenating files, slowdown

*To*: mathgroup at smc.vnet.net*Subject*: [mg53327] concatenating files, slowdown*From*: George Szpiro <george at netvision.net.il>*Date*: Thu, 6 Jan 2005 02:52:02 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

I have finally given up on shuffling 10^8 numbers, and decided to shuffle ten files of 10^7 numbers each. (ShuffledA.doc ... ShuffledJ.doc. I have Mathematica Version 4.2 and used Put[OutputForm[ to create the files.) Now I am trying to concatenate the ten files Question 1: I need quadratic time to just read the files. (See below.) WHY? Question 2: Is there an easy way to concatenate files? Thanks for any pointers, George george at netvision.net.il Timing[ OpenRead["c:\ShuffledA.doc"]; aa=Read["c:\ShuffledA.doc"]; Print["Length: ",Length[aa]]; ] From In[15]:= Length: 100000 Out[414]= {4.597 Second,Null} From In[15]:= Length: 200000 Out[18]={20.68 Second,Null} From In[15]:= Length: 400000 Out[18]= {89.679 Second,Null} --