At 9:34 PM +0000 10/31/10, Brian wrote:
Thanks for the previous help, that triggered a few dormant grey cells :-)
and leads me to another question.
I would like to compare 2 (unsorted) csv files..
file 1 contains
fredbloggs,0
joebloggs,3
joeblow,6
file 2
fredbloggs,1
joebloggs,4
replace the value in file 2 with the value in file 1.
if the item in file 1 doesn't exist in file 2, insert/append the line
so that
file 2 becomes
fredbloggs,0
joebloggs,4
joeblow,6
How big are your files? If they are not too big, I would do the following:
1. Read file 1, remove the end-of-line (EOL) character from each
line, split the line into two strings, save the two strings in a hash.
2. Read file 2, remove the EOL, split the line, check to see if the
key exists in the hash and, if it does, replace the second field with
the corresponding hash value. write out the line, and (here is the
tricky part) delete the hash entry.
3. Iterate over the hash entries that remain and add them to the end
of the file.
Note: this will only work if the key values in file 1 and 2 are unique.
Can you write the code for each of these steps?
For information on the Perl functions you need, see the following:
perldoc -f open
perldoc -f chomp
perldoc -f split
perldoc -f exists
perldoc -f delete
--
Jim Gibson
j...@gibson.org
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