Question

5

Searching for patterns in csv files

rated 0 times [ 5] [ 0] / answers: 1 / hits: 2534 / 3 Years ago, sat, june 5, 2021, 9:17:03

I have file.csv that looks like this

4,6,18,23,26

5,12,19,29,31

2,5,13,16,30

9,10,24,27,32

4,5,10,19,22

4,6,8,10,25

2,3,4,25,11

I want to find some patterns and save them in another log file file.log and remove them from the first file. Perl or grep ideally

for instance, if x+1 = x2, in range of 3, remove the row and log its existence in another file and where it existed. So then 2,4,5,25,11 will be removed from file.csv and in file.log I would find something like row 7: 2,3,4,25,11 was removed from file.csv. I'm trying to find sequences

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answered 3 Years ago ovierman · Accepted Answer

If we interpret your requirement to mean that the value of the third field (column) should be one more than that of the second field (column), then with awk you can do things like

awk -F, '

$3==$2+1 {print "row "NR": "$0" was removed from "FILENAME > "file.log"; next}1

' file.csv > newfile.csv

which will create your file.log as specified and write the remaining lines to newfile.csv. You can rename newfile.csv to file.csv after to simulate deletion.