short if else

[Moneypenny]

Hy,

I've got an short ifelse notation, but can give only one action like:

$test == 1 ? $do = true : $do = false;

But this gives an parse error:

$test == 1 ? $do = true $who = "me" : $do = false;
or
$test == 1 ? $do = true; $who = "me"; : $do = false;

All gives a parse error.

How can i do this?

Tnx.

[Kimmo Laine]

"Moneypenny" <ge******@planet.nl> wrote in message
news:43***********************@text.nova.planet.nl ...

Hy,

I've got an short ifelse notation, but can give only one action like:

$test == 1 ? $do = true : $do = false;

But this gives an parse error:

$test == 1 ? $do = true $who = "me" : $do = false;
or
$test == 1 ? $do = true; $who = "me"; : $do = false;

$test==1 ? $do = true : $do = false;
$test==1 ? $who = 'me' : 0 ;

(in this particular case it could be expressed as:
($do = $test==1) ? $who = 'me' : '';
in order to make it really short)

You _could_ do it the way you intended to do it, but that would be bad
coding practise, so I'm not gonna say how.

--
"En ole paha ihminen, mutta omenat ovat elinkeinoni." -Perttu Sirviö
an*******************@gmail.com.NOSPAM.invalid

[iuz]

Kimmo Laine wrote:

"Moneypenny" <ge******@planet.nl> wrote in message
news:43***********************@text.nova.planet.nl ...

Hy,

[..]
$test==1 ? $do = true : $do = false;
$test==1 ? $who = 'me' : 0 ;

(in this particular case it could be expressed as:
($do = $test==1) ? $who = 'me' : '';
in order to make it really short)

You _could_ do it the way you intended to do it, but that would be bad
coding practise, so I'm not gonna say how.

but this way the third part of the ternary operator is not required so..
$do = $test == 1 && $who = 'me';
IMHO is the shortest way to make it..

--
www.iuz-lab.info

[Shelly]

Why? Why not go with standard if/else?

[David Haynes]

iuz wrote:

Kimmo Laine wrote:

"Moneypenny" <ge******@planet.nl> wrote in message
news:43***********************@text.nova.planet.nl ...

Hy,

[..]

$test==1 ? $do = true : $do = false;
$test==1 ? $who = 'me' : 0 ;

(in this particular case it could be expressed as:
($do = $test==1) ? $who = 'me' : '';
in order to make it really short)

You _could_ do it the way you intended to do it, but that would be bad
coding practise, so I'm not gonna say how.

but this way the third part of the ternary operator is not required so..
$do = $test == 1 && $who = 'me';
IMHO is the shortest way to make it..

Leaving issues such as maintainability and clarity aside...

$do = $test && $who = 'me';

Since $do = $test will be resolved as boolean by the && operator.

-david-

[black francis]

try:

$do = ($test == 1) ? true : false;

regards.

[Oli Filth]

black francis said the following on 28/12/2005 14:37:

try:

$do = ($test == 1) ? true : false;

Well, that can be shortened to:

$do = ($test == 1);
--
Oli

[Oli Filth]

David Haynes said the following on 28/12/2005 12:31:

iuz wrote:

Kimmo Laine wrote:

"Moneypenny" <ge******@planet.nl> wrote in message
news:43***********************@text.nova.planet.nl ...

Hy,

[..]

$test==1 ? $do = true : $do = false;
$test==1 ? $who = 'me' : 0 ;

(in this particular case it could be expressed as:
($do = $test==1) ? $who = 'me' : '';
in order to make it really short)

You _could_ do it the way you intended to do it, but that would be bad
coding practise, so I'm not gonna say how.

but this way the third part of the ternary operator is not required so..
$do = $test == 1 && $who = 'me';
IMHO is the shortest way to make it..

Leaving issues such as maintainability and clarity aside...

$do = $test && $who = 'me';

Since $do = $test will be resolved as boolean by the && operator.

This will only work, of course, if we are assuming that the failure
condition is (0 == $test), and not (1 != $test).
--
Oli

[David Haynes]

Oli Filth wrote:

black francis said the following on 28/12/2005 14:37:

try:

$do = ($test == 1) ? true : false;

Well, that can be shortened to:

$do = ($test == 1);

Which can be shortened to:

$do = $test;

unless $test = 0, $do will evaluate as false.

-david-

[Oli Filth]

Moneypenny said the following on 28/12/2005 10:51:

Hy,

I've got an short ifelse notation, but can give only one action like:

$test == 1 ? $do = true : $do = false;

But this gives an parse error:

$test == 1 ? $do = true $who = "me" : $do = false;
or
$test == 1 ? $do = true; $who = "me"; : $do = false;

All gives a parse error.

How can i do this?

Use a standard if-else. The ternary operator ?: is *not*, repeat *not*,
a short-hand form for if() {...} else {...}.

It's designed to be used to evaluate a value that's dependent on some
condition, i.e.:

$result = ($test_expression) ? $val_if_true : $val_if_false;

Now, it just so happens that assignments (e.g. $do = true in your
example above) resolve to a value, and so can be used as $val_if_true or
$val_if_false. Don't let that fool you into thinking that you can
execute arbitrary blocks of code inside a ternary statement.

--
Oli

[Oli Filth]

David Haynes said the following on 28/12/2005 14:42:

Oli Filth wrote:

black francis said the following on 28/12/2005 14:37:

try:

$do = ($test == 1) ? true : false;

Well, that can be shortened to:

$do = ($test == 1);

Which can be shortened to:

$do = $test;

unless $test = 0, $do will evaluate as false.

Technically, it's not the same. In the first two examples, $do will
*always* be a boolean. But in your new version, $do could be anything,
dependent on what type $test is.
--
Oli

[Oli Filth]

Oli Filth said the following on 28/12/2005 14:53:

David Haynes said the following on 28/12/2005 14:42:

Oli Filth wrote:

black francis said the following on 28/12/2005 14:37:

try:

$do = ($test == 1) ? true : false;

Well, that can be shortened to:

$do = ($test == 1);

Which can be shortened to:

$do = $test;

unless $test = 0, $do will evaluate as false.

Technically, it's not the same. In the first two examples, $do will
*always* be a boolean. But in your new version, $do could be anything,
dependent on what type $test is.

Oh, and another thing. With:

$do = ($test == 1);

$do will resolve to true *only* if ($test == 1), i.e. will resolve to
false for any other value of $test.
With:

$do = $test;

$do will resolve to false *only* if ($test == 0), i.e. will resolve to
true for any other value of $test.
--
Oli

[David Haynes]

Oli Filth wrote:

David Haynes said the following on 28/12/2005 14:42:

Oli Filth wrote:

black francis said the following on 28/12/2005 14:37:

try:

$do = ($test == 1) ? true : false;
Well, that can be shortened to:

$do = ($test == 1);

Which can be shortened to:

$do = $test;

unless $test = 0, $do will evaluate as false.

Technically, it's not the same. In the first two examples, $do will
*always* be a boolean. But in your new version, $do could be anything,
dependent on what type $test is.

I disagree. My version simply relies on the casting rules for int to
boolean. The example where ($test == 1) implicitly says that $test is of
type integer not boolean since we know it would be $do = ($test == true)
if $test was boolean.

Ah! The joys of loosely typed languages...

-david-

[Oli Filth]

David Haynes said the following on 28/12/2005 15:44:

Oli Filth wrote:

David Haynes said the following on 28/12/2005 14:42:

Oli Filth wrote:

black francis said the following on 28/12/2005 14:37:

> try:
>
> $do = ($test == 1) ? true : false;

Well, that can be shortened to:

$do = ($test == 1);

Which can be shortened to:

$do = $test;

unless $test = 0, $do will evaluate as false.

Technically, it's not the same. In the first two examples, $do will
*always* be a boolean. But in your new version, $do could be anything,
dependent on what type $test is.

I disagree. My version simply relies on the casting rules for int to
boolean. The example where ($test == 1) implicitly says that $test is of
type integer not boolean since we know it would be $do = ($test == true)
if $test was boolean.

I'm not sure what you're disagreeing with.

$do = ($test == 1) ? true : false;
and
$do = ($test == 1);

are exactly equivalent in every respect.

Whereas:

$do = $test;

not only results in $do being an integer (or whatever type $test is),
but when evaluated as a boolean (e.g. if ($do) {...}), does not result
in the same success/failure conditions. In fact, all you're doing is
copying the value, so this version achieves nothing!

--
Oli

[Mladen Gogala]

On Wed, 28 Dec 2005 11:51:29 +0100, Moneypenny wrote:

All gives a parse error.

How can i do this?

Tnx.

Well, everything else aside, there is a trick you can use:

$ cat /tmp/ttt
#!/usr/local/bin/php
<?php
$test=1;
$test == 1 ? eval('$do = true; $who = "me";') : $do = false;
echo "Do: $do Who:$who\n";
?>

$ php /tmp/ttt
Do: 1 Who:me
$

Of course, the code would be much more readable with if/then,
just as the others have told you.

--
http://www.mgogala.com

[Kimmo Laine]

"Mladen Gogala" <go****@sbcglobal.net> kirjoitti
viestissä:pa****************************@sbcglobal .net...

On Wed, 28 Dec 2005 11:51:29 +0100, Moneypenny wrote:

All gives a parse error.

How can i do this?

Tnx.

Well, everything else aside, there is a trick you can use:

$ cat /tmp/ttt
#!/usr/local/bin/php
<?php
$test=1;
$test == 1 ? eval('$do = true; $who = "me";') : $do = false;
echo "Do: $do Who:$who\n";
?>

$ php /tmp/ttt
Do: 1 Who:me
$

Yep, this is the one I was thinking. But NO. Let me say that just one more
time, NOOOO! As I said this would be very bad coding practise, since there
is no reason to use eval to write a shorthand if-else. It's just stupid. How
I wish you hadn't brought it up. And yet you did... It is said that if you
need to use eval, you're not doing it right. Using eval and the ternary
operator instead of if and else is not the choice of a sane person.

--
SETI @ Home - Donate your cpu's idle time to science.
Further reading at <http://setiweb.ssl.berkeley.edu/>
Kimmo Laine <an*******************@gmail.com.NOSPAM.invalid>

[Mladen Gogala]

On Wed, 28 Dec 2005 21:53:08 +0200, Kimmo Laine wrote:

Using eval and the ternary
operator instead of if and else is not the choice of a sane person.

I agree, it is bad coding, but it was a nice problem to solve.
I had fun.

--
http://www.mgogala.com