Hi,

I have this sample file:

660312,MIKE , 138555.51
660312,MIKE , 219132.05
660312,MIKE , 246677.63
660312,MIKE , 268489.41 >>>>this record to be repeated
670182,JOHN , 155591.30
670182,JOHN , 246753.39
670182,JOHN , 279279.87
670182,JOHN , 303745.03
670182,JOHN , 408252.03 >>>>this record to be repeated

I am trying to repeat the last record where $1 is not matching with the next record.

awk -F, '{if(p!=$1){print $0; p=$1}print $0}'
But this is repeating the very first record after the condition is met.

Help will be appreciated.

On 7/19/2021 6:55 AM, raj wrote:
> Hi,
>
> I have this sample file:
>
> 660312,MIKE , 138555.51
> 660312,MIKE , 219132.05
> 660312,MIKE , 246677.63
> 660312,MIKE , 268489.41 >>>>this record to be repeated
> 670182,JOHN , 155591.30
> 670182,JOHN , 246753.39
> 670182,JOHN , 279279.87
> 670182,JOHN , 303745.03
> 670182,JOHN , 408252.03 >>>>this record to be repeated
>
> I am trying to repeat the last record where $1 is not matching with the next record.
>
> awk -F, '{if(p!=$1){print $0; p=$1}print $0}'
> But this is repeating the very first record after the condition is met.
>
> Help will be appreciated.

$ awk -F',' '
p1 != $1 { if (NR>1) print p0 }
{ print; p1=$1; p0=$0 }
END { print p0 }
' file
660312,MIKE , 138555.51
660312,MIKE , 219132.05
660312,MIKE , 246677.63
660312,MIKE , 268489.41 >>>>this record to be repeated
660312,MIKE , 268489.41 >>>>this record to be repeated
670182,JOHN , 155591.30
670182,JOHN , 246753.39
670182,JOHN , 279279.87
670182,JOHN , 303745.03
670182,JOHN , 408252.03 >>>>this record to be repeated
670182,JOHN , 408252.03 >>>>this record to be repeated

Regards,

Ed.

On 19.07.2021 13:55, raj wrote:
> Hi,
>
> I have this sample file:
>
> 660312,MIKE , 138555.51
> 660312,MIKE , 219132.05
> 660312,MIKE , 246677.63
> 660312,MIKE , 268489.41 >>>>this record to be repeated
> 670182,JOHN , 155591.30
> 670182,JOHN , 246753.39
> 670182,JOHN , 279279.87
> 670182,JOHN , 303745.03
> 670182,JOHN , 408252.03 >>>>this record to be repeated
>
> I am trying to repeat the last record where $1 is not matching with the next record.
>
> awk -F, '{if(p!=$1){print $0; p=$1}print $0}'
> But this is repeating the very first record after the condition is met.
>
> Help will be appreciated.

Maybe something like this...

awk -F, 'p && $1!=p {print d}; {p=$1; d=$0 }; 1; END{print d}'

Janis

On Monday, 19 July 2021 at 18:07:01 UTC+5:30, Janis Papanagnou wrote:
> On 19.07.2021 13:55, raj wrote:
> > Hi,
> >
> > I have this sample file:
> >
> > 660312,MIKE , 138555.51
> > 660312,MIKE , 219132.05
> > 660312,MIKE , 246677.63
> > 660312,MIKE , 268489.41 >>>>this record to be repeated
> > 670182,JOHN , 155591.30
> > 670182,JOHN , 246753.39
> > 670182,JOHN , 279279.87
> > 670182,JOHN , 303745.03
> > 670182,JOHN , 408252.03 >>>>this record to be repeated
> >
> > I am trying to repeat the last record where $1 is not matching with the next record.
> >
> > awk -F, '{if(p!=$1){print $0; p=$1}print $0}'
> > But this is repeating the very first record after the condition is met.
> >
> > Help will be appreciated.
> Maybe something like this...
>
> awk -F, 'p && $1!=p {print d}; {p=$1; d=$0 }; 1; END{print d}'
>
>
> Janis

Thank you very much

In article <29cb9f58-7a9a-4e2b-a732-3d9a4661ccaen@googlegroups.com>,
raj <visitnag@gmail.com> wrote:
>Hi,
>
>I have this sample file:
>
>660312,MIKE , 138555.51
>660312,MIKE , 219132.05
>660312,MIKE , 246677.63
>660312,MIKE , 268489.41 >>>>this record to be repeated
>670182,JOHN , 155591.30
>670182,JOHN , 246753.39
>670182,JOHN , 279279.87
>670182,JOHN , 303745.03
>670182,JOHN , 408252.03 >>>>this record to be repeated
>
>I am trying to repeat the last record where $1 is not matching with the next record.
>
>awk -F, '{if(p!=$1){print $0; p=$1}print $0}'
>But this is repeating the very first record after the condition is met.

Others have given solutions using flag variables and such, that are
designed to work regardless of file size, but here's the way I'd look at
this problem. I'd assume that the file size isn't an issue - i.e., that
your file is probably not that big, and that the definition of a "big" file
on modern machines is orders of magnitude larger than what your grandfather
(and the original designers of AWK) would have considered to be a "big" file.

A pretty large fraction of the AWK programs that I write follow a general
pattern of:

1) In the main pattern/action space, build up an array "myArray".

2) In the END clause, dump out myArray.

This pattern fits your problem well. I'd do something like (untested):

--- Cut Here ---
BEGIN { FS="," }
{ myArray[$1] = $0 } # Keep only the last one seen.
END { setsort(2);for (i in myArray) print myArray[i] }
--- Cut Here ---

Now, the only issue is the order in which the final output comes. You may
not care what order the output is, in which case, you can leave out the
call to setsort(). Or, you can be aware that setsort(2) will make it come
out in ascending numeric order.

And, in fact, assuming you are using GAWK, it should come out in ascending
numeric order even without using setsort(). This seems to be a
barely-documented feature of GAWK - that if array indices are all numeric,
they will come out sorted numerically, even without explicitly setting the
sort order.

--
"You can safely assume that you have created God in your own image when
it turns out that God hates all the same people you do." -- Anne Lamott