Thursday, April 7, 2022

[SOLVED] AWK, SED to display a column based on Column name

Issue

I am working on a shell script which has a lot of SED and AWK commands in it. Now, I am stuck up in a place where i couldn't proceed further.

For example :- If i run the below command. It prints the first column. 

awk 'OFS="\t" {print $1;}' finename.txt

But, Is there a way to print a particular column using column name instead of column number. Guess there is no straight forward way to do it, But there should be some trick to do this.

Sample data(tab seperated)

  itemNumber  Price   Mango   Apple   Bannana
   112201      purchased   need-to-plan    purchased
   112202  55  yet-to-buy  yet-to-buy  purchased
   112202  67  need-to-plan    purchased   purchased
   112203  456 need-to-plan    need-to-plan    need-to-plan
   112203  33  need-to-plan    yet-to-buy  need-to-plan
   112204  456 need-to-plan    yet-to-buy  need-to-plan
   112204      yet-to-buy  purchased   need-to-plan
   112205  77  yet-to-buy  purchased   need-to-plan
   112205  99  yet-to-buy  purchased   yet-to-buy
   112206  0   yet-to-buy  purchased   yet-to-buy

Solution

Something like this?

awk -vcol=Price '(NR==1){colnum=-1;for(i=1;i<=NF;i++)if($(i)==col)colnum=i;}{print $(colnum)}' filename.csv

I should explain:

  • -v sets a variable, so with -vcol=Price I'm declaring the column that I'm looking for.
  • The (NR==1) selects the first line and the code after that searches through the column headers for the one we want to print.
  • Finally we print the column.

For multiple columns the approach is similar:

awk -F'\t' -vcols=fun,coming '(NR==1){n=split(cols,cs,",");for(c=1;c<=n;c++){for(i=1;i<=NF;i++)if($(i)==cs[c])ci[c]=i}}{for(i=1;i<=n;i++)printf "%s" FS,$(ci[i]);printf "\n"}' filename.csv


Answered By - Max Murphy
Answer Checked By - Cary Denson (WPSolving Admin)
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