Php operators

PHP Operator is a symbol i.e. used to perform operations on operands.
For example: $num=10+20;
PHP Operators can be categorized in following forms:
Arithmetic Operators
Bitwise Operators
Logical Operators
String Operators
Incrementing/Decrementing Operators
Array Operators
Assignment Operators
PHP Comments
PHP comments can be used to describe any line of code so that other developer can understand the code easily. It can also be used to hide any code.
PHP supports single line and multi line comments.
PHP Single Line Comments
// (C++ style single line comment)
# (Unix Shell style single line comment)
  

1. PHP Operators PHP Operator is a symbol i.e. used to perform operations on operands. For example: $num=10+20 ; PHP Operators can be categorized in following forms: Arithmetic Operators Bitwise Operators Logical Operators String Operators Incrementing/Decrementing Operators Array Operators Assignment Operators

2. PHP comments can be used to describe any line of code so that other developer can understand the code easily. It can also be used to hide any code. PHP supports single line and multi line comments . PHP Single Line Comments // (C++ style single line comment) # (Unix Shell style single line comment ) <? php    //  this is C++ style single line comment   #  this is Unix Shell style single line comment   echo  "Welcome to PHP single line comments";   ?>    PHP Comments

3. In PHP, we can comments multiple lines also. To do so, we need to enclose all lines within /* */ <? php    /*   Anything  placed  within  comment  will  not be displayed  on  the browser;  */    echo  "Welcome to PHP multi line comment";   ?>    PHP Multi Line Comments

4. PHP if else statement is used to test condition. There are various ways to use if statement in PHP. if if-else if-else-if nested if PHP If Else

5. PHP if statement is executed if condition is true . Syntax: if (condition ){   // code to be executed   }    Example: <? php    $ num=12;   if ($num<100){   echo  "$num is less than 100";   }    ?>    PHP If Statement

6. PHP if-else statement is executed whether condition is true or false . Syntax: if (condition){   // code to be executed if true   } else {   // code to be executed if false   }    Example: <? php    $ num=12;   if ($num%2==0){   echo  "$num is even number";   } else {   echo  "$num is odd number";   }    ?>    PHP If-else Statement

7. PHP switch statement is used to execute one statement from multiple conditions. It works like PHP if-else-if statement . Syntax: switch (expression){       case  value1:        //code to be executed     break ;   case  value2:        //code to be executed     break ;   ......        default :        code to be executed  if  all cases are not matched;     }    PHP Switch

8. PHP Switch Example <? php      $num=20;     switch ($num){     case  10:     echo("number is equals to 10");     break ;     case  20:     echo("number is equal to 20");     break ;     case  30:     echo("number is equal to 30");     break ;     default :     echo("number is not equal to 10, 20 or 30");     }    ?>    

9. PHP for loop can be used to traverse set of code for the specified number of times. It should be used if number of iteration is known otherwise use while loop . Syntax: for (initialization; condition;  inc./ dec .){    // code to be executed   }    PHP For Loop <?php   for ($n=1;$n<=10;$n++){   echo "$n<br/>";   }   ?>  

10. We can use for loop inside for loop in PHP, it is known as nested for loop. PHP Nested For Loop <?php   for ($i=1;$i<=3;$i++){   for ($j=1;$j<=3;$j++){   echo "$i   $j<br/>";   }   }   ?>  

11. PHP for each loop is used to traverse array elements. Syntax foreach ( $array  as  $ var  ){  // code to be executed   }    ?>    PHP For Each Loop <? php    $season= array (" summer","winter","spring","autumn ");   foreach ( $season  as  $ arr  ){     echo "Season is: $ arr < br  />";   }   ?>  

12. PHP while loop can be used to traverse set of code like for loop. It should be used if number of iteration is not known. PHP While Loop Syntax while (condition){   //code to be executed   }   Alternative Syntax while (condition):   //code to be executed      endwhile ;   <?php   $n=1;   while ($n<=10){   echo "$n<br/>";   $n++;   }   ?>  

13. PHP do while loop can be used to traverse set of code like php while loop. The PHP do-while loop is guaranteed to run at least once. It executes the code at least one time always because condition is checked after executing the code. PHP do while loop Syntax do {   //code to be executed   } while (condition);   Example <?php   $n=1;   do {   echo "$n<br/>";   $n++;   } while ($n<=10);   ?>  

14. PHP break statement breaks the execution of current for, while, do-while, switch and for-each loop. If you use break inside inner loop, it breaks the execution of inner loop only. Syntax jump statement;   break ;   PHP Break <?php   for ($i=1;$i<=10;$i++){   echo "$i <br/>";   if ($i==5){   break ;   }   }   ?>  

15. PHP function is a piece of code that can be reused many times. It can take input as argument list and return value. There are thousands of built-in functions in PHP . Advantage of PHP Functions Code Reusability Less Code Easy to understand PHP Functions

16. We can declare and call user-defined functions easily.  Function name must be start with letter and underscore only like other labels in PHP. It can't be start with numbers or special symbols. PHP User-defined Functions Syntax function   functionname (){   //code to be executed   }   <? php    function   sayHello (){   echo "Hello PHP Function";   }   sayHello ();//calling function   ?>  

17. We can pass the information in PHP function through arguments which is separated by comma. PHP supports  Call by Value  (default),  Call by Reference ,  Default argument values  and  Variable-length argument list . PHP Function Arguments <? php    function   sayHello ($name){   echo "Hello $name< br />";   }   sayHello (" Sonoo ");   sayHello (" Vimal ");   sayHello ("John");   ?>   <? php    function   sayHello ($ name,$age ){   echo "Hello $name, you are $age years old< br />";   }   sayHello ("Sonoo",27);   sayHello ("Vimal",29);   sayHello ("John",23);   ?>  

18. Value passed to the function doesn't modify the actual value by default (call by value). But we can do so by passing value as a reference. By default, value passed to the function is call by value. To pass value as a reference, you need to use ampersand (&) symbol before the argument name. PHP Call By Reference <? php    function  adder(&$str2)   {       $str2 .= 'Call By Reference';   }   $ str  = 'Hello ';   adder($ str );   echo $ str ;   ?>  

19. We can specify a default argument value in function. While calling PHP function if you don't specify any argument, it will take the default argument. Default Argument Value <? php    function   sayHello ($name=" Sonoo "){   echo "Hello $name< br />";   }   sayHello ("Rajesh");   sayHello ();//passing no value   sayHello ("John");   ?>  

20. Returning Value <? php    function  cube($n){   return  $n*$n*$n;   }   echo "Cube of 3 is: ".cube(3);   ?>