[25678] in Perl-Users-Digest
Perl-Users Digest, Issue: 7919 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Mar 29 13:17:25 2005
Date: Tue, 29 Mar 2005 10:17:19 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Tue, 29 Mar 2005 Volume: 10 Number: 7919
Today's topics:
Re: slicing syntax question <clarke@n_o_s_p_a_m_hyperformix.com>
Re: slicing syntax question <tadmc@augustmail.com>
Re: slicing syntax question xhoster@gmail.com
Re: slicing syntax question xhoster@gmail.com
Re: sorting matrixes <xah@xahlee.org>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 25 Mar 2005 08:31:46 -0600
From: "AC" <clarke@n_o_s_p_a_m_hyperformix.com>
Subject: Re: slicing syntax question
Message-Id: <424420b2$0$3713$39cecf19@news.twtelecom.net>
<robic0@yahoo.com> wrote in message
news:1111732795.625462.276760@f14g2000cwb.googlegroups.com...
> "I really want to use fewer lines in my code ......"
>
> Why is that... do you think fewer lines makes your code run more
> effeciently.
> You may think its terrible to make a mistake in front of syntax gods,
> but I
> assure you that content, clarity and logic ... in any language, is much
> more important.
>
Understood. I was actually thinking that there would be an idiom so that
clarity would be assumed.
Allan
------------------------------
Date: Fri, 25 Mar 2005 08:48:52 -0600
From: Tad McClellan <tadmc@augustmail.com>
Subject: Re: slicing syntax question
Message-Id: <slrnd4896k.ba1.tadmc@magna.augustmail.com>
robic0@yahoo.com <robic0@yahoo.com> wrote:
> Why is that... do you think fewer lines makes your code run more
> effeciently.
Do you think that questions end with a question mark?
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: 25 Mar 2005 17:33:57 GMT
From: xhoster@gmail.com
Subject: Re: slicing syntax question
Message-Id: <20050325123357.611$sZ@newsreader.com>
"AC" <clarke@n_o_s_p_a_m_hyperformix.com> wrote:
> Why does this fail with a syntax error
>
> my @items = qw(a b c d e);
> my @hash{@items} = 0..$#items;
>
> but this does not?
>
> my @items = qw(a b c d e);
> @hash{@items} = 0..$#items;
Because one has a syntax error and the other does not. It would be nice
if perl allowed you to declare a hash while using it in a slice,
but sadly it does not.
>
> I really want to use fewer lines in my code and I'd hate to use one line
> to declare the hash and one line to initialize it.
newlines are optional almost everywhere in Perl.
my %hash; @hash{@items}= 0..$#items;
Cheers,
Xho
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------------------------------
Date: 25 Mar 2005 17:47:38 GMT
From: xhoster@gmail.com
Subject: Re: slicing syntax question
Message-Id: <20050325124738.572$vA@newsreader.com>
"robic0@yahoo.com" <robic0@yahoo.com> wrote:
> "I really want to use fewer lines in my code ......"
>
> Why is that... do you think fewer lines makes your code run more
> effeciently.
No, but it can make maintaining the code more efficient. It I can see an
entire logical unit of the program on the screen without have to keep
scolling up and down, that makes things a lot easier. Wise use of white
space, and wise non-use of white-space, both contribute to good coding
style.
Xho
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Usenet Newsgroup Service $9.95/Month 30GB
------------------------------
Date: 27 Mar 2005 20:24:38 -0800
From: "Xah Lee" <xah@xahlee.org>
Subject: Re: sorting matrixes
Message-Id: <1111983878.706828.54230@o13g2000cwo.googlegroups.com>
Here's the solution to previous post.
-------------------------------
perl code:
sub sort_matrix($$) {
my $ref_matrix =3D $_[0];
my @indexMatrix =3D @{$_[1]};
my @indexes =3D map {$_->[0]} @indexMatrix;
my @operators =3D map {$_->[1] ? ' cmp ' : ' <=3D> '} @indexMatrix;
my @directions =3D map {$_->[2]} @indexMatrix;
my $body_code =3D '';
my @body_array;
for (my $i =3D 0; $i <=3D $#indexes; $i++) {
if ($directions[$i]) {
push(@body_array, "(\$a->[$i]" . $operators[$i] .
"\$b->[$i])");
} else {
push(@body_array, "(\$b->[$i]" . $operators[$i] .
"\$a->[$i])");
};
};
$body_code =3D join( ' or ', @body_array);
my $array_code =3D '(map { [' . join(q(, ), map {"\$_->[$_]"}
@indexes) . ', $_]} @$ref_matrix)';
my $code =3D "map {\$_->[-1]} (sort { $body_code} $array_code)";
my @result =3D eval $code;
return [@result];
};
------------------------------------------
Python code
# python v 2.4
def sort_matrix(matrix, directives):
result=3Dmatrix
for dir in directives:
if dir[1]:
if dir[2]:
result.sort(lambda x,y: cmp( str(x[dir[0]]),
str(y[dir[0]])) )
else:
result.sort(lambda x,y: cmp( str(x[dir[0]]),
str(y[dir[0]])), None, True)
else:
if dir[2]:
result.sort(lambda x,y: cmp(float(x[dir[0]]),
float(y[dir[0]])) )
else:
result.sort(lambda x,y: cmp(float(x[dir[0]]),
float(y[dir[0]])), None, True )
return result
m =3D [
[3, 99, 'a'],
[2, 77, 'a'],
[1, 77, 'a']
]
print sort_matrix(m,[
[2,True,True],
[1,False,True]
])
The Python code has not been tested much.
http://xahlee.org/perl-python/sort_matrix.html
Xah
xah@xahlee.org
=E2=88=91 http://xahlee.org/PageTwo_dir/more.html
=E2=98=84
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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End of Perl-Users Digest V10 Issue 7919
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