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What is the Best way to determine # of line in a...

Rudolph Ten

Joined: Jan 23, 2002
Posts: 9
What is the Best way to determine the number of lines in a file to process in Java....
These files have over 100,000 lines.....
I wanted to do a count so then i can calculate and show the percentage done processed.....
currently i do 2 passes at file...
I read every record to get a total line count.
Once i have this count....i re-read file again to process each record individually
Both passes are slow.....
But on FIRST PASS.....IS there a way to figure out how many lines my file has? Or a faster way to read them for count?(on first pass)
Java Newbie
Adam Hardy
Ranch Hand

Joined: Oct 09, 2001
Posts: 567
Can't you read the file size from the file system & use that instead?

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Donny Wi

Joined: Jan 24, 2002
Posts: 13
If you are running your program in UNIX, you can try to count the number of lines using UNIX's "wc -l" command for the first run. FYI, you can use Java Runtime class to run Unix program from java.
The second loop can be done in java to do the data processing.
[ February 03, 2002: Message edited by: Donny Wi ]

Donny Widjaja
Les Dsouza

Joined: Jan 29, 2002
Posts: 27
You can try the length()method in File object, this returns the number of bytes. Now as you read each line keep track of the number of bytes read so far.
Hope this helps.
I agree. Here's the link:
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