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}
--