CODEWITHSUNDEEP
linuxawk
user3270725
user3270725

Reputation: 133

copy one value to selected rows

I have file like

A 1  2
A 1
A 1
B 2  3
B 2
B 2

I would like to copy the 2 in all A 1. I.e if($1="A" && $2==1) print value that is $3. I have tried like using awk but not able to get the result.

The result could be

A 1  2
A 1  2
A 1  2
B 2  3
B 2  3
B 2  3

Thanking you in advance

Upvotes: 0

Views: 78

Answers (3)

Aserre
Aserre

Reputation: 5072

Try awk '{$3 == ""{print $0, var; next} {var=$3; print}' myfile

Note that this works only for your format, and only if at least the 1st line of your file has a 3rd column

As I didn't know wether validation was crucial for your script, this doesn't check for validity of 2nd field (i.e. this will append 2 even if you have A 5), nor does it check the 1st one (i.e., having a file like this :

A 1 2
B 2

will output

A 1 2
B 2 2

However, if you use it with files formated like the one you showed as an example, it will work exactly as you want. This will even work if you add 

C 3 4
C 3
...

Upvotes: 0

Jotne
Jotne

Reputation: 41460

Here is a small awk that should do:

awk '$3!="" {t=$3} {$3=t} 1'    
A 1 2
A 1 2
A 1 2
B 2 3
B 2 3
B 2 3

Or this:

 awk '$3 || $3=="0" {t=$3} {$3=t} 1' file

Upvotes: 1

Kent
Kent

Reputation: 195159

based on the example and your codes, this may help you:

awk 'NF==3{a[$1,$2]=$3}NF<3{$3=a[$1,$2]}7' file

Upvotes: 2

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