UNIX for Dummies Questions & Answers

Hi,

I've shown an example of what I would like to achieve below. In the example file, I would like to sum the values in column 2 for each distinct category in column 3 (presumably making an array?) and print the sum as well as the category name and length (note:length always corresponds with name). In case it matters, the actual file is huge with many rows and columns. Any notes on what the commands do would also be fantastic if anyone has time to do this.

Thanks!!


example input file:

coord,value,name,length
1,2,alpha,4
2,4,alpha,4
3,5,alpha,4
4,0,alpha,4
5,0,beta,5
6,12,beta,5
7,2,beta,5
8,5,beta,5
9,3,beta,5
10,13,gamma,3
11,3,gamma,3
12,0,gamma,3

request output file:

value_sum,name,length
11,alpha,4
22,beta,5
16,gamma,3

Try:

Code:

awk -F, '{A[$3","$4]+=$2} END{for (i in A) print A[i]","i}' infile

Hi,

Unfortuantely, my output with this command is just "0,,"
I also tried gawk instead of awk but got the same results.
Any advice?

Thanks!

Hi, did you use:

Code:

-F,

I have no problem getting the output based on Scrutinizer suggestion:

awk -F, '{A[$3","$4]+=$2} END{for (i in A) print A[i]","i}' input
22,beta,5
16,gamma,3
11,alpha,4

Yes, I used the whole command line exactly as written. Not sure why it didn't work...

- You could try if this makes a difference:

Code:

awk -F"," '{A[$3","$4]+=$2} END{for (i in A) print A[i]","i}' infile

- Did you specify the right input file?
- Does the input file use a comma as the separator?