Why? ! vs <

[cc4digital]

Hello everyone.  This is a logic question that I am trying to figure out.

 

Why does this not mean the same thing?

 

if(!$lowgradelevel<$highgradelevel)  VS if($lowgradelevel>$highgradelevel

 

 

Thanks

[sKunKbad]

You might think of the ! as making things backwards.

 

So:

 

if( 3>2) means if 3 is greater than 2

 

if( ! 3>2 ) means if 3 is not greater than 2

 

if (3<2) is the same as if(!3>2) because ! makes it backwards

 

This is a really simple, and perhaps lame way of explaining it, but since you asked, then you probably need to read a book on php!

[AbraCadaver]

You might think of the ! as making things backwards.

 

So:

 

if( 3>2) means if 3 is greater than 2

 

if( ! 3>2 ) means if 3 is not greater than 2

 

if (3<2) is the same as if(!3>2) because ! makes it backwards

 

This is a really simple, and perhaps lame way of explaining it, but since you asked, then you probably need to read a book on php!

 

Partially. The ! operator take precedence over < and > so this is really what's happening (makes a difference when you start adding more expressions):

 

if( ! 3>2 ) NOT 3 (which evaluates to false) > 2 = false (false>2=false)

 

This actually negates the comparison as described earlier:

 

if( ! (3>2) ) 3 > 2 = true (NOT true=false)

 

[btherl]

The oppposite of < is >=, and the opposite of > is <=.  That's another way to invert the comparisons.