Comparing fields and deleting columns

[Jalr2003]

I have the following file

A B C D E F G
- - - - - - -
1 2 3 4 5 6 7
1 3 3 4 8 6 8

I want to compare lines 2 and 3 column by column, and print the complete column when those two values are different.

In this case, the intended output would be

B E G
- - -
2 5 7
3 8 8

Is there a way to do that using awk or nawk?

The input file will always have 4 lines, but can have as many as 30 columns. I just want to be able to show the columns where the values changed.

Thanks

Jalr2003

 

[marsd]

You could adapt something like this:

{

    for (x=1 ; x <= NF ; x++) {
         if (NR > 2 && xold[x] && $x != xold[x]) {
            printf(&quot;At %d -- %d : %s ! %s\n&quot;,NR,x,xold[x], $x)
          }
         if ($x ~ /[0-9]+/) {xold[x] = $x}
    }
}

Test:
File = {
A B C D E F G
- - - - - - -
1 2 3 4 5 6 7
1 3 3 4 8 6 8
5 2 1 5 9 2 3
}

Output:
At 4 -- 2 : 2 ! 3
At 4 -- 5 : 5 ! 8
At 4 -- 7 : 7 ! 8
At 5 -- 1 : 1 ! 5
At 5 -- 2 : 3 ! 2
At 5 -- 3 : 3 ! 1
At 5 -- 4 : 4 ! 5
At 5 -- 5 : 8 ! 9
At 5 -- 6 : 6 ! 2
At 5 -- 7 : 8 ! 3

 

[CaKiwi]

Or something like this?

BEGIN {
getline
n1 = split($0,a1)
getline
getline
n2 = split($0,a2)
getline
n3 = split($0,a3)
for(j=1;j<=n3;j++) if (a2[j]!=a3[j]) printf a1[j] &quot; &quot;
print &quot;&quot;
for(j=1;j<=n3;j++) if (a2[j]!=a3[j]) printf &quot;- &quot;
print &quot;&quot;
for(j=1;j<=n3;j++) if (a2[j]!=a3[j]) printf a2[j] &quot; &quot;
print &quot;&quot;
for(j=1;j<=n3;j++) if (a2[j]!=a3[j]) printf a3[j] &quot; &quot;
print &quot;&quot;
exit
}

You might need to check whether n1, n2 and n3 are equal and format the output better.

CaKiwi

&quot;I love mankind, it's people I can't stand&quot; - Linus Van Pelt

 

[Jalr2003]

I tried caKiwi's suggestion, but I got blank lines in the output.

Any ideas why this happens?

Thanks for your answers,

Jalr2003

 

[CaKiwi]

Put some debug print statements after the splits

printf n1
for (j=1;j<=n1;j++) printf &quot; &quot; a1[j]
print &quot;&quot;

CaKiwi

&quot;I love mankind, it's people I can't stand&quot; - Linus Van Pelt

 

[Jalr2003]

Never mind,

I was missing the second line in my input file.

Thaks,

Jalr2003

 

[Jalr2003]

One last question,

The lenght of the fields that I have in my input file is not the same. What can I do to get a better organized output.

I have for input something like this:

SYS_ID LIMIT CODE PART_NUM
------ ---- ---- --------
16447 15 1NB 4A0001
19631 14 1NB 4A0001

I changed one of your lines from:

for(j=1;j<=n3;j++) if (a2[j]!=a3[j]) printf &quot;- &quot;

to:

for(j=1;j<=n3;j++) if (a2[j]!=a3[j]) printf a2[j] &quot; &quot;

I get the disered output, but it is disorganized.

Thanks again,

Jalr2003

 

[CaKiwi]

If the fields are all the same length, use something like

for(j=1;j<=n3;j++) if (a2[j]!=a3[j]) printf a2[j] substr(&quot; &quot;,1,8-length(a2[j]))

If they are not the same length, create an array, len say, containing the length of each and replace the above substr by

substr(&quot; &quot;,1,len[j]-length(a2[j]))


CaKiwi

&quot;I love mankind, it's people I can't stand&quot; - Linus Van Pelt

 

[Jalr2003]

Thanks for your help,

I am starting learning about awk, and I am not sure how I can create the array in this case.

Could you help me with that?

Thanks,

Jalr2003

 

[CaKiwi]

The simplest way would be

len[1]=6;len[2]=6;len[3]=6;....

or if you prefer

split(&quot;6,6,6,4,8,6,8&quot;,len,&quot;,&quot

CaKiwi

&quot;I love mankind, it's people I can't stand&quot; - Linus Van Pelt

 

[Jalr2003]

Thanks CaKiwi

It certainly looks better!

However, I just noticed something.

If I have an imput like this

A B C D E F G H
- - - - - - - -
1 2 3 4 6 6
2 3 2 4 6 7

my output is

A B C F
- - - -
1 2 3 6
2 3 2 7

As you see, column B gets the values of C, because there are less columns in rows 2 and 3.

Is there a way to eliminate columns B and F, before doing what you suggested?

Thanks again,

Jalr2003

 

[CaKiwi]

If your data can have blank fields, You will need to use substr instead of split to break them up.

BEGIN {
split(&quot;4,4,4,4,4,4,4&quot;,len,&quot;,&quot
getline
n1 = split($0,a1)
getline
getline
for (j=1;j<=n1;j++) a2[j] = substr($0,(j-1)*len[j]+1,len[j])
getline
for (j=1;j<=n1;j++) a3[j] = substr($0,(j-1)*len[j]+1,len[j])
for(j=1;j<=n1;j++) if (a2[j]!=a3[j]) printf a1[j] &quot; &quot;
print &quot;&quot;
for(j=1;j<=n1;j++) if (a2[j]!=a3[j]) printf &quot;- &quot;
print &quot;&quot;
for(j=1;j<=n1;j++) if (a2[j]!=a3[j]) printf a2[j] &quot; &quot;
print &quot;&quot;
for(j=1;j<=n1;j++) if (a2[j]!=a3[j]) printf a3[j] &quot; &quot;
print &quot;&quot;
exit
}

CaKiwi

&quot;I love mankind, it's people I can't stand&quot; - Linus Van Pelt