3 ms·

Concretely, awk -F, -v OFS=, {print $2+$3, $1, $2, $3}' foo.csv | sort -n | cut -d, -f2-

by em500 6y ago

enriquto 6y ago
I think this code does not fulfill the task: you need to sum columns 4 and 7, and keep the rest of the data intact in the output.
- em500 6y ago
  You're right, that should be awk -F, -v OFS=, '{print $4+$7, $0}' foo.csv | sort -n -k1 -t, | cut -f2- -d, Explanation: awk -F, -v OFS=, sets the input and output column separator to comma, '{print $4+$7, $0}' outputs the sum of column 4 and 7 before the rest of the line. sort -n -k1 -t, sorts the file numerically on column 1, with comma separator. cut -f2- -d, removes column 1, with comma separator. This is of course not robust for general CSV files, but I don't think OPs marcel is either. A robust solution requires a proper CSV parser. The biggest warts I see in the classic unix solution is that all the tools use different flags for the field separator. edit: if you know that the csv doesn't contain tabs, you can omit some flags for a more concise awk -F, -v OFS='\t' '{print $4+$7,$0}' foo.csv | sort -n -k1 | cut -f2- since sort and cut default to tabs/whitespace as separators. If you're unsure about the contents of the CSV, you really need a proper CSV parser.
  - enriquto 6y ago
    At the end, it doesn't look that bad. Of course using the csv format is a bad start in unix. Much better to convert everything to tsv and work from there. In that case the "obvious" shell solution is quite clear. <foo.tsv awk '{print $4+$7,$0}' | sort -n -k1 | cut -f2-
  - geophile 6y ago
    > This is of course not robust for general CSV files, but I don't think OPs marcel is either. A robust solution requires a proper CSV parser. I haven't tested corner cases, but marcel relies on the python csv module, which is probably better than any initial attempt at a parser that I could write in an hour. This is what I meant about sublanguages. Many people, (myself included), would need to go to the man pages to find the necessary arguments to awk, sort, and cut. I find it much easier to just write a little Python, even if the end result involves more typing.

Concretely, awk -F, -v OFS=, {print $2+$3, $1, $2, $3}' foo.csv | sort -n | cut -d, -f2-

by em500 6y ago

Concretely, awk -F, -v OFS=, {print $2+$3, $1, $2, $3}' foo.csv | sort -n | cut -d, -f2-

I think this code does not fulfill the task: you need to sum columns 4 and 7, and keep the rest of the data intact in the output.

em500 6y ago
You're right, that should be awk -F, -v OFS=, '{print $4+$7, $0}' foo.csv | sort -n -k1 -t, | cut -f2- -d, Explanation: awk -F, -v OFS=, sets the input and output column separator to comma, '{print $4+$7, $0}' outputs the sum of column 4 and 7 before the rest of the line. sort -n -k1 -t, sorts the file numerically on column 1, with comma separator. cut -f2- -d, removes column 1, with comma separator. This is of course not robust for general CSV files, but I don't think OPs marcel is either. A robust solution requires a proper CSV parser. The biggest warts I see in the classic unix solution is that all the tools use different flags for the field separator. edit: if you know that the csv doesn't contain tabs, you can omit some flags for a more concise awk -F, -v OFS='\t' '{print $4+$7,$0}' foo.csv | sort -n -k1 | cut -f2- since sort and cut default to tabs/whitespace as separators. If you're unsure about the contents of the CSV, you really need a proper CSV parser.
- enriquto 6y ago
  At the end, it doesn't look that bad. Of course using the csv format is a bad start in unix. Much better to convert everything to tsv and work from there. In that case the "obvious" shell solution is quite clear. <foo.tsv awk '{print $4+$7,$0}' | sort -n -k1 | cut -f2-
- geophile 6y ago
  > This is of course not robust for general CSV files, but I don't think OPs marcel is either. A robust solution requires a proper CSV parser. I haven't tested corner cases, but marcel relies on the python csv module, which is probably better than any initial attempt at a parser that I could write in an hour. This is what I meant about sublanguages. Many people, (myself included), would need to go to the man pages to find the necessary arguments to awk, sort, and cut. I find it much easier to just write a little Python, even if the end result involves more typing.