Monday, July 31, 2017

Operators are used to perform operations on variables and values.

PHP divides the operators in the following groups:

1. Arithmetic operators
2. Assignment operators
3. Comparison operators
4. Increment/Decrement operators
5. Logical operators
6. String operators
7. Array operators
PHP Arithmetic Operators :
The PHP arithmetic operators are used with numeric values to perform common arithmetical operations, such as addition, subtraction, multiplication etc.

 Example Name Result +\$a Identity Conversion of \$a to int or float as appropriate. -\$a Negation Opposite of \$a. \$a + \$b Addition Sum of \$a and \$b. \$a - \$b Subtraction Difference of \$a and \$b. \$a * \$b Multiplication Product of \$a and \$b. \$a / \$b Division Quotient of \$a and \$b. \$a % \$b Modulo Remainder of \$a divided by \$b. \$a ** \$b Exponentiation Result of raising \$a to the \$b'th power. Introduced in PHP 5.6.

Example :1
<?php

echo (5 % 3)."\n";           // prints 2
echo (5 % -3)."\n";          // prints 2
echo (-5 % 3)."\n";          // prints -2
echo (-5 % -3)."\n";         // prints -2

?>

Example : 2
<?php
if ((\$a % 2) == 1)
{ echo "\$a is odd." ;}
if ((\$a % 2) == 0)
{ echo "\$a is even." ;}
?>

PHP Assignment Operators :
The PHP assignment operators are used with numeric values to write a value to a variable.
 Example Name Result a = b The left operand gets set to the value of the expression on the right a = b a += b Addition a = a + b a -= b Subtraction a = a - b a *= b Multiplication a = a * b a /= b Division a = a / b a %= b Modulus a = a % b

Example :1
<?php

\$a = (\$b = 4) + 5; // \$a is equal to 9 now, and \$b has been set to 4.

?>

Example : 2
<?php

\$a = 3;
\$a += 5; // sets \$a to 8, as if we had said: \$a = \$a + 5;
\$b = "Hello ";
\$b .= "There!"; // sets \$b to "Hello There!", just like \$b = \$b . "There!";

?>

PHP Comparison Operators:
The PHP comparison operators are used to compare two values (number or string):
 Example Name Result \$a == \$b Equal TRUE if \$a is equal to \$b after type juggling. \$a === \$b Identical TRUE if \$a is equal to \$b, and they are of the same type. \$a != \$b Not equal TRUE if \$a is not equal to \$b after type juggling. \$a <> \$b Not equal TRUE if \$a is not equal to \$b after type juggling. \$a !== \$b Not identical TRUE if \$a is not equal to \$b, or they are not of the same type. \$a < \$b Less than TRUE if \$a is strictly less than \$b. \$a > \$b Greater than TRUE if \$a is strictly greater than \$b. \$a <= \$b Less than or equal to TRUE if \$a is less than or equal to \$b. \$a >= \$b Greater than or equal to TRUE if \$a is greater than or equal to \$b. \$a <=> \$b Spaceship An integer less than, equal to, or greater than zero when \$a is respectively less than, equal to, or greater than \$b. Available as of PHP 7.
Example : 1

<?php
var_dump(0 == "a"); // 0 == 0 -> true
var_dump("1" == "01"); // 1 == 1 -> true
var_dump("10" == "1e1"); // 10 == 10 -> true
var_dump(100 == "1e2"); // 100 == 100 -> true

switch ("a") {
case 0:
echo "0";
break;
case "a": // never reached because "a" is already matched with 0
echo "a";
break;
}
?>

PHP Increment / Decrement Operators :
The PHP increment operators are used to increment a variable's value.
The PHP decrement operators are used to decrement a variable's value.
 Example Name Effect ++\$a Pre-increment Increments \$a by one, then returns \$a. \$a++ Post-increment Returns \$a, then increments \$a by one. --\$a Pre-decrement Decrements \$a by one, then returns \$a. \$a-- Post-decrement Returns \$a, then decrements \$a by one.
Example : 1
<?php
echo "<h3>Postincrement</h3>";
\$a = 5;
echo "Should be 5: " . \$a++ . "<br />\n";
echo "Should be 6: " . \$a . "<br />\n";

echo "<h3>Preincrement</h3>";
\$a = 5;
echo "Should be 6: " . ++\$a . "<br />\n";
echo "Should be 6: " . \$a . "<br />\n";

echo "<h3>Postdecrement</h3>";
\$a = 5;
echo "Should be 5: " . \$a-- . "<br />\n";
echo "Should be 4: " . \$a . "<br />\n";

echo "<h3>Predecrement</h3>";
\$a = 5;
echo "Should be 4: " . --\$a . "<br />\n";
echo "Should be 4: " . \$a . "<br />\n";
?>

Output :
--------------

Should be 6: 6
Should be 6: 6

Should be 5: 5
Should be 4: 4

Predecrement

Should be 4: 4
Should be 4: 4

PHP Logical Operators :
The PHP logical operators are used to combine conditional statements.
 Example Name Result \$a and \$b And TRUE if both \$a and \$b are TRUE. \$a or \$b Or TRUE if either \$a or \$b is TRUE. \$a xor \$b Xor TRUE if either \$a or \$b is TRUE, but not both. ! \$a Not TRUE if \$a is not TRUE. \$a && \$b And TRUE if both \$a and \$b are TRUE. \$a || \$b Or TRUE if either \$a or \$b is TRUE.
Example :1
<?php
\$x = 100;
\$y = 50;

if (\$x == 100 and \$y == 50) {
echo "match found";
}
?>

Output :
---------------
match found

PHP String Operators:
PHP has two operators that are specially designed for strings.
1.  Concatenate the two variables using dot operator (.)
2. Append content using Concatenate  assignment operator (.=)

Example :1
<?php
\$a = "Hello ";
\$b = \$a . "World!"; // now \$b contains "Hello World!"

\$a = "Hello ";
\$a .= "World!";     // now \$a contains "Hello World!"
?>

PHP Array Operators:
The PHP array operators are used to compare arrays.
 Example Name Result \$a + \$b Union Union of \$a and \$b. \$a == \$b Equality TRUE if \$a and \$b have the same key/value pairs. \$a === \$b Identity TRUE if \$a and \$b have the same key/value pairs in the same order and of the same types. \$a != \$b Inequality TRUE if \$a is not equal to \$b. \$a <> \$b Inequality TRUE if \$a is not equal to \$b. \$a !== \$b Non-identity TRUE if \$a is not identical to \$b.
Example :1
<?php
\$a = array("a" => "apple", "b" => "banana");
\$b = array("a" => "pear", "b" => "strawberry", "c" => "cherry");

\$c = \$a + \$b; // Union of \$a and \$b
echo "Union of \\$a and \\$b: \n";
var_dump(\$c);

\$c = \$b + \$a; // Union of \$b and \$a
echo "Union of \\$b and \\$a: \n";
var_dump(\$c);

\$a += \$b; // Union of \$a += \$b is \$a and \$b
echo "Union of \\$a += \\$b: \n";
var_dump(\$a);
?>