reading and sorting from multiple textfiles in visual basic
$30-100 USD
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Hi,
I have following problem which i cannot solve properly.i have a large number of textfiles (ca.300, and each 10MB large) containing time ordered data for a specific stock. i would want to write a function that sorts the contents of the textfiles and reads the lines inside the textfiles line by line and orders them by time. e.g.
text file 1:
stock,time,price
WPP.L,12:31:01,123
WPP.L,12:34:05,124
WPP.L,12:38:09,125
text file 2:
stock,time,price
VOD.L 12:31:00 323
VOD.L 12:33:05 325
VOD.L 12:37:19 327
text file 3:
stock,time,price
PRTY.L,12:30:11,543
PRTY.L,12:33:15,542
PRTY.L,12:36:12,541
should result in
PRTY.L,12:30:11,543
VOD.L,12:31:00,323
WPP.L,12:31:01,123
VOD.L,12:33:05,325
PRTY.L,12:33:15,542
WPP.L,12:34:05,124
PRTY.L,12:36:12,541
VOD.L,12:37:19,327
WPP.L,12:38:09,125
since the files are very large i wouldnt want to put the files in memory but rather sorting them and reading them line by line on the fly as previously described.
I would like to avoid following approach since the files are too big to read them into memory
Use a 3D array to keep temporary data.
1. Read each file and populate this array.
2. Close the file
3. Sort the array using any sorting algorithm. (this is the heaviest part!)
4. Write the array contents to new file(s)
The reading and sorting on the fly should be very quick and efficient.
thanks
PS
i am not a great programmer and never did anything with multithreaded applications and this is just an idea. perhaps there a way one could create a multithreaded application where each thread reads one file and calls an event whenever the timestamp in a file is the next one to be displayed? This would create an asynchroneous output which would simulate a real time feed
## Deliverables
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## Platform
windwows XP, visual basic or VB.NET
项目ID： #3936783
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