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:
|
$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:
|
$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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