CODEWITHSUNDEEP
awk
Tony
Tony

Reputation: 35

How to print the user specified fields

I am writing a AWK script that is going to have the user input the fields and have the script count the amount of times each word appears in that field. I have the code set up so that it already so that it prints out all of the fields and the amount of times each word occurs but I am trying to have only the user specified fields get counted. The user will be inputting CSV files so I am setting the FS to a comma.

Knowing that AWK assumes that all arguments are that are inputted are going to be a file, I set the arguments to an array and then delete them from ARGV array so it will not throw an error. 

#!/usr/bin/awk -f
BEGIN{ FS = ",";
for(i = 1; i < ARGC-1; i++){
    arg[i] = ARGV[i];
    delete ARGV[i];
    }
}


{

for(i=1; i <=NF; i++)
    words[($i)]++

}

END{

for( i in words)
    print i, words[i];

}

So if the user inputs a CSV file such as...

A,B,D,D
Z,C,F,G
Z,A,C,D
Z,Z,C,Q

and the user wants to have only field 3 counted for the output should be...

C 3
F 1

Or if the user 1 and 3 for the fields...

A 2
B 1
C 1
Z 4

Upvotes: 0

Views: 75

Answers (2)

RavinderSingh13
RavinderSingh13

Reputation: 133760

Could you please try following(I have written this on mobile so couldn't test it).

awk -v fields="1,3" '
BEGIN{
 FS=OFS="," 
 num=split(fields,array,",")
 for(j=1;j<=num;j++){
   a[array[j]]
 }
}
{
 for(i=1;i<=NF;i++){
   if(i in a){
     count[$i]++
   }
 }
}
END{
  for(h in count){
     print h,count[h]
  }
}
'   Input_file

I believe this should work for parsing multiple Input_files too. If needed you could try passing multiple files to it.

Explanation: Following is only for explanation purposes.

-v fields="1,3" creating a variable named fields whose value is user defined, it should be comma separated, for an example I have taken 1 and 3, you could keep it as per Your need too.

BEGIN{......} starting BEGIN section here where mentioning field separator and output field separator as Comma for all lines of Input_file(s). Then using split I am splitting variable fields to an array named array whose delimiter is comma. Variable num is having length of fields variable in it. Starring a for loop from 1 to till value of num. In it creating an array named a whose index is value of array whose index is variable j value.

MAIN Section: now starting a for loop which traverse through all of the fields of lines. Then it checks if any field number is coming into array named a which we created in BEGIN section, if yes then it is creating an array named count with index of current column + taking its count too. Which we need as per OP's requirement.

Finally in this program's END section traversing through array count and printing it's indexes with their counts.

Upvotes: 2

James Brown
James Brown

Reputation: 37464

Another:

$ awk -F, -v p="1,2" '{   # parameters in comma-separated var
    split(p,f)            # split parameters to fields var
    for(i in f)           # for the given fields
        c[$f[i]]++        # count chars in them
}
END {                     # in the end
    for(i in c)
        print i,c[i]      # output chars and counts
}' file

Output for fields 1 and 2:

A 2
B 1
C 1
Z 4

Upvotes: 2

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