Logical OR will not work in if statement

this is what i have:

<?php if($row['id']!="9") echo "style=\"display:none\""; ?>  

simple enough, it should place style="dsplay:none" when 'i开发者_运维问答d' is anything but 9. this does the job well, but i wanted to include 'id' 8, 12 and 13 aswell. looked simple enough, just added the logical or like this:

<?php if($row['id']!="8||9||12||13") echo "style=\"display:none\""; ?>

but it does not function anymore, so it places style="dsplay:none" all the time.

i wanted to go the other way around and did this

<?php if($row['id']=="4||5||6||11") echo "style=\"display:none\""; ?>

but this time around style="dsplay:none"was never placed.

this brought me to the conclusion that there must be something wrong with the logical or. but what is it? please let me know, thanks!

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You want:

if($row['id']!= 8 && $row['id'] != 9 && $row['id'] != 12)

because the current way you are doing it is comparing the value of $row['id'] to the string value "8||9||12||13".

Or you can do something like:

if(in_array($row['id'], array(8, 9, 12)))

to condense the condition.

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You cannot do it like that.

Either use if($row['id'] == 4 || $row['id'] == 5 || ...) or use in_array(): if(in_array($row['id'], array(4,5,6,11)))

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I suggest you to write

<?php if(in_array($row['id'], array(8, 9, 12, 13)) /* ... */; ?>

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You're comparing numbers with strings in a way that won't work. E.g. an $row['id'] of 1 is not equal to the string "4||5||6||11".

You could use the in_array function which checks whether a value exist in an array:

if(!in_array($row['id'], array(4, 5, 6, 11)) echo ' style="display:none"';

Logical OR's (||) do not work inside strings.

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That's not logical or, that's a string literal. But De Morgan:

if(($row['id']!="8") && $row['id']!="9" && ...