echo "123f69,"|awk '$0 !~ /[A-Z]*/'

[Hongyi Zhao]

Hi all,

Perhaps it's a simple issue for here, but I cann't figure out it. Sorry
for bothering again.

See the following for detail:

werner@debian:~$ echo "123f69,"|awk '$0 !~ /[A-Z]*/'
werner@debian:~$ echo "123f69,"|awk '$0 !~ /[A-Z]+/'
123f69,

Why the first one gives nothing, while the second one will output the
original string?

According to REGEXP used here, I want awk print the line which doesn’t
contain the upper case A-Z. In this sense, I think the above two methods
are equivalent, but why they give different results?

Regards
--
.: Hongyi Zhao [ hongyi.zhao AT gmail.com ] Free as in Freedom :.

[Kenny McCormack]

In article <mgb78a$6dj$1...@aspen.stu.neva.ru>,

Hongyi Zhao <hongy...@gmail.com> wrote:
>Hi all,
>
>Perhaps it's a simple issue for here, but I cann't figure out it. Sorry
>for bothering again.
>
>See the following for detail:
>
>werner@debian:~$ echo "123f69,"|awk '$0 !~ /[A-Z]*/'
>werner@debian:~$ echo "123f69,"|awk '$0 !~ /[A-Z]+/'
>123f69,
>
>Why the first one gives nothing, while the second one will output the
>original string?

Ask yourself this question:

Does the string "123f69," contain any sequences of zero or more upper
case letters?

--

Some of the more common characteristics of Asperger syndrome include:

* Inability to think in abstract ways (eg: puns, jokes, sarcasm, etc)
* Difficulties in empathising with others
* Problems with understanding another person's point of view
* Hampered conversational ability
* Problems with controlling feelings such as anger, depression
and anxiety
* Adherence to routines and schedules, and stress if expected routine
is disrupted
* Inability to manage appropriate social conduct
* Delayed understanding of sexual codes of conduct
* A narrow field of interests. For example a person with Asperger
syndrome may focus on learning all there is to know about
baseball statistics, politics or television shows.
* Anger and aggression when things do not happen as they want
* Sensitivity to criticism
* Eccentricity
* Behaviour varies from mildly unusual to quite aggressive
and difficult

[Hongyi Zhao]

On Sat, 11 Apr 2015 13:26:44 +0000, Kenny McCormack wrote:

> Ask yourself this question:
>
> Does the string "123f69," contain any sequences of zero or more
> upper case letters?

OMG, it contains zero time sequences of upper case letters, so it doesn't
contains zero time sequences of upper case letters.

[Ed Morton]

On 4/11/2015 8:23 AM, Hongyi Zhao wrote:
> Hi all,
>
> Perhaps it's a simple issue for here, but I cann't figure out it. Sorry
> for bothering again.
>
> See the following for detail:
>
> werner@debian:~$ echo "123f69,"|awk '$0 !~ /[A-Z]*/'
> werner@debian:~$ echo "123f69,"|awk '$0 !~ /[A-Z]+/'
> 123f69,
>
> Why the first one gives nothing, while the second one will output the
> original string?

Ask yourself - what does `*` mean vs what `+` means? Rewrite your conditions as:

awk '/[A-Z]*/{next} 1'
awk '/[A-Z]+/{next} 1'

Now do you see it? How about the equivalent:

awk '/[A-Z]{0,}/{next} 1'
awk '/[A-Z]{1,}/{next} 1'

or:

awk '/[A-Z]?/{next} 1'
awk '/[A-Z]/{next} 1'

>
> According to REGEXP used here, I want awk print the line which doesn’t
> contain the upper case A-Z. In this sense, I think the above two methods
> are equivalent, but why they give different results?

Because they aren't equivalent.

Some other points:

`[A-Z]` is not necessarily just the upper case letters. In some locales A-Z
means `AbBcC...zZ`, i.e. all letters except "a". That's what the character class
[:upper:] is for.

You don't need to write `$0 ~ ` in a condition as that's the default. You could
just write awk '!/[[:upper:]]/'.

I hate that I responded to this but I couldn't stop myself. Oh well, maybe I'll
get employee of the month....

Ed.

[Hongyi Zhao]

On Sat, 11 Apr 2015 09:31:23 -0500, Ed Morton wrote:

[snip]

> I hate that I responded to this but I couldn't stop myself. Oh well,
> maybe I'll get employee of the month....

Surely, I also think so ;-)

Regards
>
> Ed.

[Ed Morton]

On 4/11/2015 6:07 PM, Hongyi Zhao wrote:
> On Sat, 11 Apr 2015 09:31:23 -0500, Ed Morton wrote:
>
> [snip]
>
>> I hate that I responded to this but I couldn't stop myself. Oh well,
>> maybe I'll get employee of the month....
>
> Surely, I also think so ;-)
>

I'm not sure if I've been employed or assimilated. I tried to resist but....

12 of 27.

[frank.w...@gmail.com]

From EdMorton:

> I hate that I responded to this but I couldn't stop myself. Oh well,
> maybe I'll get employee of the month....

Our tasking has changed from that of servants to that of
educators, so your employment is now more honorable.

Frank

[Kaz Kylheku]

If you're educating others to be servants, though, then that is hardly more
honorable than being one.

[Frank P. Westlake]

That has no relevancy to any current discussion so I don't know why you
state it.

Frank

[Javier]

> awk '/[A-Z]*/{next} 1'

May I ask what does the '1' at the end mean?

[Janis Papanagnou]

Am 13.04.2015 um 00:53 schrieb Javier:
>> awk '/[A-Z]*/{next} 1'
>
> May I ask what does the '1' at the end mean?

It's a shortcut to print the current line.

awk '
/[A-Z]*/{next}
1
'

Syntax: condition { action }

Condition "1" means 'true', and the default action is 'print $0'.

Janis

[Chris F.A. Johnson]

On 2015-04-12, Javier wrote:
>> awk '/[A-Z]*/{next} 1'
>
> May I ask what does the '1' at the end mean?

It's a non-zero pattern, so the line is printed.

--
Chris F.A. Johnson