Re: Re[6]: [PHP] Need a more elegant way of bitwise ORing values
On 13/06/07, Richard Davey [EMAIL PROTECTED] wrote:
Hi Robert,
Wednesday, June 13, 2007, 3:15:39 PM, you wrote:
It's terribly verbose and inefficient...
?php
$filter['flags'] = 0;
if( $allow_fraction )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_FRACTION;
}
if( $allow_thousand )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_THOUSAND;
}
if( $allow_scientific )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_SCIENTIFIC;
}
?
I don't think it's *terribly* verbose, as it has good sentence structure
to it, but your version is certainly more efficient, hence I've
swapped to that. Any other takers? ;)
lose the conditionals?
$filter['flags'] = 0;
$allow_fraction $filter['flags'] |= FILTER_FLAG_ALLOW_FRACTION;
$allow_thousand $filter['flags'] |= FILTER_FLAG_ALLOW_THOUSAND;
$allow_scientific $filter['flags'] |= FILTER_FLAG_ALLOW_SCIENTIFIC;
or keep the conditionals and just do one assignment?
$filter['flags'] = ($allow_fraction ? FILTER_FLAG_ALLOW_FRACTION : 0)
| ($allow_thousand ? FILTER_FLAG_ALLOW_THOUSAND : 0)
| ($allow_scientific ? FILTER_FLAG_ALLOW_SCIENTIFIC : 0);
as the perl motto says, there's more than one way to do it.
-robin
-robin
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Re: Re[6]: [PHP] Need a more elegant way of bitwise ORing values
admittedly i had to read up quickly on the usage of a *binary pattern*where each bit in said *pattern* is used to represent the state of some boolean variable. wikipedia sufficed http://en.wikipedia.org/wiki/Bitwise_operation#OR this makes much more sense to me now; as ive seen this technique before but never taken in a formal explanation of it. i hesitate now to suggest what i would do, which would be to define an object encapsulating an array of boolean variables and providing acccessors and mutators for each respective value it represented. presumably the internal implementation might be enhanced using the bitwise OR mechanism discussed in this thread, in which case we would still like to know how to best handle the implementation component of said object. but i do very much love my objects : nice thread, -nathan
Re[6]: [PHP] Need a more elegant way of bitwise ORing values
At 3:19 PM +0100 6/13/07, Richard Davey wrote:
?php
$filter['flags'] = 0;
if( $allow_fraction )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_FRACTION;
}
if( $allow_thousand )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_THOUSAND;
}
if( $allow_scientific )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_SCIENTIFIC;
}
?
I don't think it's *terribly* verbose, as it has good sentence structure
to it, but your version is certainly more efficient, hence I've
swapped to that. Any other takers? ;)
Rich:
How about?
switch (1)
{
case $allow_fraction:
$filter['flags'] = FILTER_FLAG_ALLOW_FRACTION;
break;
case $allow_thousand:
$filter['flags'] = FILTER_FLAG_ALLOW_THOUSAND;
break;
case $allow_scientific:
$filter['flags'] = FILTER_FLAG_ALLOW_SCIENTIFIC;
break;
}
Would that not work?
Cheers,
tedd
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Re[6]: [PHP] Need a more elegant way of bitwise ORing values
Hi Robert,
Wednesday, June 13, 2007, 3:15:39 PM, you wrote:
It's terribly verbose and inefficient...
?php
$filter['flags'] = 0;
if( $allow_fraction )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_FRACTION;
}
if( $allow_thousand )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_THOUSAND;
}
if( $allow_scientific )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_SCIENTIFIC;
}
?
I don't think it's *terribly* verbose, as it has good sentence structure
to it, but your version is certainly more efficient, hence I've
swapped to that. Any other takers? ;)
Cheers,
Rich
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Re: Re[6]: [PHP] Need a more elegant way of bitwise ORing values
On Wed, 2007-06-13 at 15:19 +0100, Richard Davey wrote:
Hi Robert,
Wednesday, June 13, 2007, 3:15:39 PM, you wrote:
It's terribly verbose and inefficient...
?php
$filter['flags'] = 0;
if( $allow_fraction )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_FRACTION;
}
if( $allow_thousand )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_THOUSAND;
}
if( $allow_scientific )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_SCIENTIFIC;
}
?
I don't think it's *terribly* verbose, as it has good sentence structure
to it, but your version is certainly more efficient, hence I've
swapped to that. Any other takers? ;)
Personally I hate constants (can't use non-scalar values so why get used
ot them... also they're just another point for name collision) so if it
were my own code I'd do something more like the following:
?php
$GLOBALS['filterFlags'] = array
(
'allowFraction' = 1 0,
'allowThousand' = 1 1,
'allowScientific' = 1 2,
);
// then your above code would become:
$filter['flags'] = 0;
foreach( $filterFlags as $name = $bits )
{
if( isset( $$name ) $$name )
{
$filter['flags'] |= $bits;
}
}
?
Cheers,
Rob.
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RE: Re[6]: [PHP] Need a more elegant way of bitwise ORing values
From: Richard Davey [mailto:[EMAIL PROTECTED]
Sent: Wed 13/06/2007 15:19
To: PHP List
Hi Robert,
Wednesday, June 13, 2007, 3:15:39 PM, you wrote:
It's terribly verbose and inefficient...
?php
$filter['flags'] = 0;
if( $allow_fraction )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_FRACTION;
}
if( $allow_thousand )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_THOUSAND;
}
if( $allow_scientific )
{
$filter['flags'] |= FILTER_FLAG_ALLOW_SCIENTIFIC;
}
?
I don't think it's *terribly* verbose, as it has good sentence structure
to it, but your version is certainly more efficient, hence I've
swapped to that. Any other takers? ;)
Well, I don't know about more efficient but I'd be terribly tempted to express
it like this:
$filter['flags'] = $allow_fraction ? FILTER_FLAG_ALLOW_FRACTION : 0
| $allow_thousand ? FILTER_FLAG_ALLOW_THOUSAND : 0
| $allow_scientific ? FILTER_FLAG_ALLOW_SCIENTIFIC : 0;
Whether you think this is more readable and/or less verbose probably depends on
personal taste! ;)
-
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