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Merging 2 .CSV files in Unix

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# 1  
Old 05-02-2008
Merging 2 .CSV files in Unix

I need a little help as I am a complete novice at scripting in unix. However, i am posed with an issue...Smilie i have two csv files in the following format@

001X ,,200
002X ,,300
003X ,,300
004X ,,300

001X ,,300
003X ,,500
005X ,,600

006X ,,100

I need the above to files to merged into on final file as below:

001X ,,300
002X ,,300
003X ,,500
004X ,,300
005X ,,600
006X ,,100

I have tried using the join command but that only lets me to join the two files but as you can see from the above i need the ability to be able to overwrite values from file 1 whith those in file 2.

Any assistance would be greatly appreciated.

Last edited by chachabronson; 05-06-2008 at 05:58 AM..
# 2  
Old 05-02-2008
anybody outhere with a clue???
# 3  
Old 05-04-2008
Could you clarify the logic?
Why you want 005X to be 100 and not 600?
# 4  
Old 05-06-2008
Originally Posted by radoulov
Could you clarify the logic?
Why you want 005X to be 100 and not 600?
Sorry my mistake that was due to a typo. I have edited and amended above as required.

The logic behing it is that the first csv (FILE1.CSV) file is produced but may have incorrect figures associated with it. Once the information is readily available the second csv (FILE2.CSV) is produced with the correct figures and any missing codes.

Once this has been done file 1 and file 2 need to be merged to have the correct figures from file 2 and also to include any missing codes that are on file 2 but not file 1.

I need to do this in Unix, my initial thoughts were to use the join command but not sure if this is possible but may be some use of lookup could be done... again i am a programming and unix newbie so would appreciate any assistance.

# 5  
Old 05-06-2008
Use nawk or /usr/xpg4/bn/awk on Solaris.
You may need to modify the code, if the format of your input doesn't match exactly the samples you posted.

awk 'END {
for (i=5; i<=n; i++)
  if (f2[_[i]])
    print f2[_[i]]
NR == FNR {
f2[_[n = FNR] = $1] = $0
$1 in f2 { 
$0 = f2[$1] 
delete f2[$1]
}1' FS=, OFS=, file2.csv file1.csv

Last edited by radoulov; 05-06-2008 at 09:37 AM..
# 6  
Old 05-09-2008
Thanks for your help, however i am unable to get teh code above to work.
I have had some assistance with the above from anothe forumite who gave me the following code:

cat file1.csv file2.csv >> temp
grep X temp | cut -d"," -f1 | sort -u > final2
while read line
line1=`grep $line file2.csv`
if [ $? -eq 0 ]
echo $line1 >> final_out
line2=`grep $line file1.csv`
echo $line2 >> final_out

done < final2

If anyone could explain in detail as to what is happening in the loop that would be great... i have tested the above and it works like a dream but i want to learn rather than just use code. I am a complet novice so would like a description in a basic level which will help me understand for future.

Thanks to everyone who has helped so far
# 7  
Old 08-05-2008
Join csv

Hi .. as written I tried to implement the logic.....I could successfully do the concatenation....but my file "final_2" is blank.....

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