CODEWITHSUNDEEP
php
GeekedOut
GeekedOut

Reputation: 17185

PHP snippet not working as I expected

I have this variable: $logged_in_person_rsvp - its value = -1

Then I run this code: 

$yes_checked = ($logged_in_person_rsvp===1) ? "checked" : "";
$maybe_checked = ($logged_in_person_rsvp===-1) ? "checked" : "";
$no_checked = ($logged_in_person_rsvp===0) ? "checked" : "";

echo '<p>logged_in_person_rsvp: '.$maybe_checked.'</p>';

And I get output as nothing. But I was expecting the output to be -1

Anyone understand why? This is weird syntax I inherited :)

Upvotes: 2

Views: 81

Answers (6)

Drew
Drew

Reputation: 1777

Have you tried var_dump($logged_in_person_rsvp); (or inspecting the value in xdebug, or firephp, or your choice of debugger) to determine what type $logged_in_person_rsvp is?

Using the snippet you provided, if I set:

$logged_in_person_rsvp = -1;

everything works fine, and I get <p>logged_in_person_rsvp: checked</p> but if I set:

$logged_in_person_rsvp = "-1";

then I get <p>logged_in_person_rsvp: </p>

As it has been pointed out by others, == will try to cast the two sides of the comparison to the same type, but === will check type as well and fail if one is a string and one is an int/float.

Upvotes: 0

Eric Yang
Eric Yang

Reputation: 1889

Ternary operations should be enclosed in parentheses.

$maybe_checked = ($logged_in_person_rsvp===-1 ? "checked" : "");

That should do the trick.

EDIT: Also, make sure that your $logged_in_person_rsvp is -1 the integer, not '-1' the string. Or try using == instead of ===.

Upvotes: 1

mario
mario

Reputation: 145482

The ternary syntax is often confusing for newcomers. This is an alternative way using an array-map to express your code:

$checked = array(FALSE => "", TRUE => "checked");

$yes_checked =   $checked[($logged_in_person_rsvp===1)];
$maybe_checked = $checked[($logged_in_person_rsvp===-1)];
$no_checked =    $checked[($logged_in_person_rsvp===0)];

echo '<p>logged_in_person_rsvp: '.$maybe_checked.'</p>';

The === is just a strict version of the normal equal == operator.

Upvotes: 1

gdub
gdub

Reputation: 301

The value of each one of these variables will be either "checked" or "", depending on the result of the operation in the brackets.

($logged_in_person_rsvp===-1) ? "checked" : "";

basically, what this does is check whether $logged_in_person_rsvp===-1 is true or false. If it is true, the variable will be assigned "checked", if it is false, the variable will be assigned "".

Upvotes: 1

ldg
ldg

Reputation: 9402

Try using two equals signs like "==" instead of 3 and see if that makes a difference. If so, your strict comparison is probably messing up your intended result.

Upvotes: 3

Rick Su
Rick Su

Reputation: 16440

you have echoed $maybe_checked

and $maybe_checked would be either "checked" or "", how would you expect it to be -1?

echoing $logged_in_person_rsvp should output -1

===================

Respond to your comment:

then try use operator == instead

=== is strict comparison between two variables

Upvotes: 3

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