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Remove Duplicate Lines When Parsing CSV

Posted on 2007-12-04
Medium Priority
Last Modified: 2008-02-01
I am using Java to read lines from a text file.  In this case, it is a CSV.  I parse the file and process each line based on my application.  I noticed that sometimes the file contains duplicate lines.  Instead of processing the duplicate line multiple times, I would like to somehow remove the duplicate lines from the CSV and then process each line in the file.  Can someone instruct me on the one of the more efficient ways of doing this?  Thanks
Question by:pcarrollnf
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LVL 86

Accepted Solution

CEHJ earned 500 total points
ID: 20405022
If it's not too big you can save the file to a Set<String>. That will ensure uniqueness

Author Comment

ID: 20405043
That's would be an issue.  These CSV files can become large and may contain thousands of lines.
LVL 86

Expert Comment

ID: 20405108
What OS are you using?
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Author Comment

ID: 20405193
Windows 2000, 2003
LVL 86

Expert Comment

ID: 20405968
Get a Windows port of textutils from http://gnuwin32.sourceforge.net. You can then do

cat orig.csv | sort | uniq >uniq.csv

Doubt if you'll get much more efficient than that

Expert Comment

ID: 20406102
There is a software called Clippy that does what you want.

LVL 92

Expert Comment

ID: 20406402
you don't need to store the entire csv in memory, just the unique keys.
That will allow you to check each line as you process it
LVL 86

Expert Comment

ID: 20781397

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