Basics | José da Cruz

Following previous posts, lets start with the basics.

Variables:

– Always start with $ and can have the following chars _ [a-z] [A-Z] and [0-9]. the first symbol must be an _ ou a letter.

$count = 0;
$name = “José Cruz”

What about types? If you know python, ruby or the “var x = 0;” construction from C# you know how PHP works. It converts the variable for the type defined by the value initialized. For instance: $count = 0; will be an “integer”.

Lets use some variables in our script:

        Learning PHP – Step 2


                $name = "José Cruz";
         echo $name . " is starting to understand PHP!";
        ?>

If you run the script above it will display “José Cruz is starting to understand PHP!”

PS: The dot between $name and “ is starting… ” is the concatenation in strings. This is new. Other languages usually use the plus sign or some function to do it.

The operators are the same as C or mainstream languages:

Arithmetic: +, ++, –, –, *, /, %

Assignment: =, +=, –=, *=, /=, %=, .=

Comparasion: ==, <=, <, >= >, <>, !=

Logic: &&, ||, !

PS: You can use “(“ and “)”

Some examples:

$a = 5 + 2 * (7 + 5);
$a++;
$b = $a –4;
$c = $a / $b;
$even = 10 % 2;

$a+=7; // same as $a = $a + 7;
$even = 10;
$even %= 2;

$verytrue = 2 < 7;
$veryfalse = 6 >= 3;
if( $a > 3 ) …. // future post we talk about if and other statements.

if( $a > 3 && $b < 10 || $even == 0 ) …

As with other languages:

– Unary operators precede all other ones ( “!” )

– then: *, / and &&

– Last: +, –, ||

Lets try this in our php website:

        Learning PHP – Step 2


                 $name = "José Cruz";
         $even = 10 % 2;
         $odd = 10 % 3;
         $someValue = $even * 4;

         echo $name . " is starting to understand PHP with some operators" . "
";
         echo "even values: ". $even . "
";
         echo "odd values: ". $odd . "
";
         echo "some value = " + $someValue . "
";
        ?>

Run it!

Next post: statements.

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Learning PHP – Step 3 Basics