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Basics of PHP

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Comment system in PHP

<?php //This is single line comment ?>
<?php
/*
This is multi line comments.
It contents any no. of line to comment in PHP
*/
?>

Writing comment to your code is good coding practice habit as it will provide you help in future to understand the code or in case you hand over the project to other developer will help them to understand too.

Data Type is PHP

Unlike other technology, PHP provides you flexibility to write any data type things into varaible starts from $ sign.

<?php
$txt = "Hello world!";
$x = 5;
$y = 10.5;
?>

PHP Variables Scope

  1. Local Scope
  2. Global Scope
  3. Static Scope
<?php
$global = 200; //this is global variable and can be called and used anywhere.
function abc()
{
$local = 400; //this is local variable can be called inside only.
global=600; //this is global can can be used anywhere.
$static = 900; // it is same as global but it value remain same through out the processing.
}
echo abc();

PHP Operators

PHP Arithmetic Operators

Operator Name Example Result
+ Addition $x + $y Sum of $x and $y
Subtraction $x – $y Difference of $x and $y
* Multiplication $x * $y Product of $x and $y
/ Division $x / $y Quotient of $x and $y
% Modulus $x % $y Remainder of $x divided by $y
** Exponentiation $x ** $y Result of raising $x to the $y’th power

PHP Assignment Operators

Assignment Same as… Description
x = y x = y The left operand gets set to the value of the expression on the right
x += y x = x + y Addition
x -= y x = x – y Subtraction
x *= y x = x * y Multiplication
x /= y x = x / y Division
x %= y x = x % y Modulus

PHP Comparison Operators

Operator Name Example Result
== Equal $x == $y Returns true if $x is equal to $y
=== Identical $x === $y Returns true if $x is equal to $y, and they are of the same type
!= Not equal $x != $y Returns true if $x is not equal to $y
<>  Not equal $x <> $y Returns true if $x is not equal to $y
!== Not identical $x !== $y Returns true if $x is not equal to $y, or they are not of the same type
Greater than $x > $y Returns true if $x is greater than $y
Less than $x < $y Returns true if $x is less than $y
>= Greater than or equal to $x >= $y Returns true if $x is greater than or equal to $y
<= Less than or equal to $x <= $y Returns true if $x is less than or equal to $y
<=> Spaceship $x <=> $y Returns an integer less than, equal to, or greater than zero, depending on if $x is less than, equal to, or greater than $y. Introduced in PHP 7.

PHP Increment / Decrement Operators

Operator Name Description
++$x Pre-increment Increments $x by one, then returns $x
$x++ Post-increment Returns $x, then increments $x by one
–$x Pre-decrement Decrements $x by one, then returns $x
$x– Post-decrement Returns $x, then decrements $x by one

PHP Logical Operators

The PHP logical operators are used to combine conditional statements.

Operator Name Example Result
and And $x and $y True if both $x and $y are true
or Or $x or $y True if either $x or $y is true
xor Xor $x xor $y True if either $x or $y is true, but not both
&& And $x && $y True if both $x and $y are true
|| Or $x || $y True if either $x or $y is true
! Not !$x True if $x is not true

PHP String Operators

PHP has two operators that are specially designed for strings.

Operator Name Example Result
. Concatenation $txt1 . $txt2 Concatenation of $txt1 and $txt2
.= Concatenation assignment $txt1 .= $txt2 Appends $txt2 to $txt1

PHP Array Operators

The PHP array operators are used to compare arrays.

Operator Name Example Result
+ Union $x + $y Union of $x and $y
== Equality $x == $y Returns true if $x and $y have the same key/value pairs
=== Identity $x === $y Returns true if $x and $y have the same key/value pairs in the same order and of the same types
!= Inequality $x != $y Returns true if $x is not equal to $y
<>  Inequality $x <> $y Returns true if $x is not equal to $y
!== Non-identity $x !== $y Returns true if $x is not identical to $y

PHP Conditional Assignment Operators

The PHP conditional assignment operators are used to set a value depending on conditions:

Operator Name Example Result
?: Ternary $x = expr1 ? expr2 : expr3 Returns the value of $x.
The value of $x is expr2 if expr1 = TRUE.
The value of $x is expr3 if expr1 = FALSE
?? Null coalescing $x = expr1 ?? expr2 Returns the value of $x.
The value of $x is expr1 if expr1 exists, and is not NULL.
If expr1 does not exist, or is NULL, the value of $x is expr2.
Introduced in PHP 7

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