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Ghostdog74 | AWK Query

Hi,

You posted on a query I had over a data manipulation task. The code you wrote seems well structured and I would like to understand it a little more.

Code:

awk 'BEGIN{OFS=FS=", "

 c["N"]="01"

 c["C"]="02"

 c["L"]="03"

}

NR==1{print}

NR>1{ 

 print $1,$2, c[substr($3,1,1)] substr($3,2) "01"

}

' file

From what I understand so far, the BEGIN OFS skips the first line. I can see that variable (?) "c" is detailing the first two numbers to use. How does this work?

Then NR displays the first line? Then I get stuck on the substr syntax.

If you could explain a little more it would be helpful. I need to amend the script so that in an event that a code's 3 characters (after the first character) are the same as another codes three characters, the 01 at the end will increment by 1.

Example:-

CBUPP = 02BUP01
CBUPI = 02BUP02
CBUPK = 02BUP03

At the moment the script will obviously produce the following:-

02BUP01
02BUP01
02BUP01

Thanks for the help.

I think ghostdog74 is the first LQ member you can search in the thread titles, now! ;)

Bookmark & read this: http://www.grymoire.com/Unix/Awk.html
Come back if it still isn't clear.

Quote:

Originally Posted by lmedland (Post 3247525)

From what I understand so far, the BEGIN OFS skips the first line. I can see that variable (?) "c" is detailing the first two numbers to use. How does this work?

the BEGIN{} block is a place where you initialize variables. ie, before awk process the files. "c" is called associative arrays. They are equivalent to this piece of code snippet

Code:

if ( var=="N" ) {

 c="01

}else if ( var=="C" ) {

 c="02"

}

Quote:

Then NR displays the first line? Then I get stuck on the substr syntax.

NR means record number. The first line , NR == 1. Second record, NR==2 and so on. As for substr, you can read about it in the manual (or the one chris provided)

Quote:

Originally Posted by ghostdog74 (Post 3247987)

the BEGIN{} block is a place where you initialize variables. ie, before awk process the files. "c" is called associative arrays. They are equivalent to this piece of code snippet

Code:

if ( var=="N" ) {

 c="01

}else if ( var=="C" ) {

 c="02"

}

NR means record number. The first line , NR == 1. Second record, NR==2 and so on. As for substr, you can read about it in the manual (or the one chris provided)

Thanks for the info everyone. :)