CODEWITHSUNDEEP
shellawksh
Oh God
Oh God

Reputation: 47

Shell script: how can i get the second element separated by comma


How can I calculate the number of occurences of the second value e.g.:'Rv1408' ? i want to get and calculate the total number of occurrences of the 2nd element in each line.<.br>

file.txt:

Rv0729,Rv1408,Rv1408  
Rv0162c,Rv0761,Rv1862,Rv3086  
Rv2790c,Rv1408
Rv2fd90c,Rv1408
Rv1862,Rv3086
Rvsf62,Rv3086

i tried(doesnt work) input:

awk ' { tot[$0]++ } END { for (i in tot) print tot[i],i } ' m.txt | sort | cut --delimiter=',' --fields=1

Expected Output:

total no of occurences: 
Rv1408: 3
Rv0761:1
Rv3086: 2

idk why i cannot get the second element even if i type fields=2

Upvotes: 1

Views: 546

Answers (2)

Daweo
Daweo

Reputation: 36370

idk why i cannot get the second element even if i type fields=2

When you are providing more than 1 argument to print GNU AWK does join that arguments using output field separator (OFS) which by default is space, yet you informed cut that it should treat , as delimiter.

If you must use awk output piped into cut then make sure that output field separator of awk and delimiter of cut is same, you have basically three options,

awk 'BEGIN{OFS=","}END{print 11,22,33}' emptyfile.txt | cut --delimiter=',' --fields=2
awk 'END{print 11,22,33}' emptyfile.txt | cut --delimiter=' ' --fields=2
awk 'BEGIN{OFS="\t"}END{print 11,22,33}' emptyfile.txt | cut --fields=2

all of them give same output

22

Explanation: 1st option is to explicitly set OFS and --delimiter to same character in both commands (, in example), 2nd option is to set --delimiter to default value of OFS which is space, 3rd option is to set OFS to default value of --delimiter which is TAB character.

Warning in most cases there is no need to pipe awk output to cut as task might be done entirely in awk.

Upvotes: 0

Serve Laurijssen
Serve Laurijssen

Reputation: 9733

You can make it easier by passing the -F comma field separator.

Like this:

awk -F, '{map[$2]++} END { for (key in map) { print key, map[key] } }' file.txt

Upvotes: 1

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