From Newsgroup: comp.lang.awk

The other day I found myself unable to count field sizes accurately so I
wrote this little helper.

NR == 1 { # Pick a line
print
nf = split(FIELDWIDTHS, fw)
for (i = 1; i <= nf; i++)
for (j = 1; j <= fw[i]; j++)
printf "%d", (i % 10)
print ""
}


Example:

with FIELDWIDTHS = "1 3 5"

Output:

A dummy line from a file
122233333
--
Bruce Horrocks
Hampshire, England

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From Newsgroup: comp.lang.awk

On 8/6/2025 4:23 AM, Bruce wrote:

The other day I found myself unable to count field sizes accurately so I wrote this little helper.

NR == 1 { # Pick a line
    print
    nf = split(FIELDWIDTHS, fw)
    for (i = 1; i <= nf; i++)
        for (j = 1; j <= fw[i]; j++)
            printf "%d", (i % 10)
    print ""
}

FWIW you could do that without nested loops and without using
FIELDWIDTHS so it'll work in any POSIX awk, not just gawk:

NR == 1 { # Pick a line
for (i = 1; i <= NF; i++) {
out = sprintf("%*s", length($i), "")
gsub(/ /, i%10, out)
printf "%s", out
}
print ""
}

Regards,

Ed.
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From Newsgroup: comp.lang.awk

On 2025-08-10, Ed Morton <mortonspam@gmail.com> wrote:

On 8/6/2025 4:23 AM, Bruce wrote:

The other day I found myself unable to count field sizes accurately so I
wrote this little helper.

NR == 1 { # Pick a line
    print
    nf = split(FIELDWIDTHS, fw)
    for (i = 1; i <= nf; i++)
        for (j = 1; j <= fw[i]; j++)
            printf "%d", (i % 10)
    print ""
}

FWIW you could do that without nested loops and without using
FIELDWIDTHS so it'll work in any POSIX awk, not just gawk:

But I suspect that the program is intended to be a helper
when developing a program that uses FIELDWIDTHS.

Your portable example is no longer testing/displaying what the value of FIELDWIDTHS is doing against the input data.
--
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca
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From Newsgroup: comp.lang.awk

In article <20250810124827.931@kylheku.com>,
Kaz Kylheku <643-408-1753@kylheku.com> wrote:
...

But I suspect that the program is intended to be a helper
when developing a program that uses FIELDWIDTHS.

Your portable example is no longer testing/displaying what the value of >FIELDWIDTHS is doing against the input data.

It is pretty clear that Mr. Ed completely missed the point of the post.

He should not feel bad about that. It is pretty obscure. It took me a few reads to get it. I was half-way though posting a "WTF is this?" post in response, when it dawned on me what the point of it was.
--
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From Newsgroup: comp.lang.awk

On 2025-08-10, Kenny McCormack <gazelle@shell.xmission.com> wrote:

In article <20250810124827.931@kylheku.com>,
Kaz Kylheku <643-408-1753@kylheku.com> wrote:
...

But I suspect that the program is intended to be a helper
when developing a program that uses FIELDWIDTHS.

Your portable example is no longer testing/displaying what the value of >>FIELDWIDTHS is doing against the input data.

It is pretty clear that Mr. Ed completely missed the point of the post.

He should not feel bad about that. It is pretty obscure. It took me a few reads to get it. I was half-way though posting a "WTF is this?" post in response, when it dawned on me what the point of it was.

Yeah; some people can't be bothered to communicate.

E.g.

"I have come up with a nice debugging aid that helps me fine-tune
the values of FIELDWDITHS to correctly match my input.

I simply take a stab at some FIELDWIDTHS values and then run
this code against some actual input.

The code prints the input record verbatim, then splits into fields
using the proposed FIELDWIDTHS, and finally prints a representation of
the field widths under the data to make it obvious what part of the data belongs to each field."
--
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal
Mastodon: @Kazinator@mstdn.ca
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From Newsgroup: comp.lang.awk

On 06.08.2025 11:23, Bruce wrote:

The other day I found myself unable to count field sizes accurately so I wrote this little helper.

It's nice, but it should at least be mentioned that it supports only
the subset of GNU Awk's FIELDWIDTHS syntax variants as you depicted
it; like "1 3 5". While the optional final '*' would be no issue -
since the purpose is obviously to create the correct numbers for the FIELDWIDTHS variable - the optional "skip-space" specification might
be an issue.

For example; for you sample data "A dummy line from a file" I suppose
you'd want to rather obtain a FIELDWIDTHS = "1 1:5 1:4 1:4 1:1 1:4";
and the helper doesn't help you here. (Although an extension of your
tool could be written.)

Some of the confusion that was reported in this thread could likely
have been alleviated by a better fitting data sample. Maybe

FIELDWIDTHS = "1 5 4 4 1 4" # test spec

ADummyLineFromAFile # input
1222223333444456666 # output

would have made the intention clearer.

Janis

NR == 1 { # Pick a line
print
nf = split(FIELDWIDTHS, fw)
for (i = 1; i <= nf; i++)
for (j = 1; j <= fw[i]; j++)
printf "%d", (i % 10)
print ""
}

Example:

with FIELDWIDTHS = "1 3 5"

Output:

A dummy line from a file
122233333

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