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1 PHP operators

PHP operators

PHP has a wide variety of operators

These operators can be distinguished into two groups: binaries, which act on two operands and unaries, which only require one operand

Thus, its general syntax is:

operand1 operator_Binary operand2

operand1 operator_unary

operator_unary operand1

Arithmetic operators

PHP supplies basic operations with the only additions of operators that return the rest of the division between the left and right operators; and the exponentiation, which allows to raise the left operator to the power of the right operator

Arithmetic operators
+	Addition
–	Subtraction
*	Multiplication
/	Division
%	Rest
**	Exponentiation

Note In other languages the + operator applied to strings concatenates both strings into a single

However, in PHP to perform this operation the operator is used.

$a = 5;
$b = 3;

$suma = $a + $b; #addition example
echo $suma; #will return us 8

$resta $a - $b #subtraction example
echo $resta; #will return us 2

$mult = $a * $b; #multiplication example
echo $mult; #will return us 15

$div = $a / $b; #division example
echo $div; #will return us 1.6667
#we must bear in mind that there is no data typing and will return a decimal value by default

$rest = $a % $b; #example of the rest of the division
echo $rest; #will return us 2

$pot = $a ** $b; #exponentiation example
echo $pot; #will return us 125

Operators of increase (++) and decrease (- -)

These operators are unary operators and they autoincremento and the autodecremento to the variable that applies to them

In addition to modifying the variable, they return the value of the variable

The operator increment or decrement can go before p behind the variable having a different meaning

If the operator is ++, it is placed after the variable is called post-increment, by first taking the value and then increasing the variable by one unit

$n = 0;
$k = 2;

$n = $k++; #The value of $k is assigned to $n, and then $k is increased
echo $n . ' ' . $k; #will return us that the value of $n was 2 and that of $k was 3

If the ++ operator is placed before the variable, it is called pre-increment and makes that first to increase in a unit variable and then take the value

$n = 0;
$k = 2;

$n = ++$k; #The value of $k is increased, and then it is assigned to $n
echo $n . ' ' . $k; #will return us that the value of $n was 3 and that of $k was 3

If the operator is - - it is placed after the variable, it is called post-decrement, making it take the value first and then the variable is decremented by one unit

$n = 0;
$k = 2;

$n = $k--; #The value of $k is assigned to $ n, and then $k is decremented
echo $n . ' ' . $k; #will return us that the value of $n was 2 and that of $k was 1

If the operator - - is placed before the variable, it is called pre-decrement and makes that first decremente in a unit variable and then take the value

$n = 0;
$k = 2;

$n = --$k; #The value of $k is decremented, and then assigned to $n
echo $n . ' ' . $k; #will return to us that the value of $n was 1 and that of $k was 1

Relational operators

Are used typically in the conditional expression

The relational operators return boolean values

The operands can be numerical or strings

Relational operators
>	Greater than
<	Less than
> =	Greater than or equal to
< =	Less than or equal to
! =	Other than that
< >	It's equivalent to ! =
! = =	Different than and of the same type
= =	Like
= = =	Same as y of the same type
< = >	Order Comparison (Added in PHP 7) 0 when they're the same -1 when the first operator is less than the second operator 1 when the first operator is larger than the second
? ?	Returns its first operand if it exists and is not NULL Otherwise it returns its second operand (Added in PHP 7)

$a = 20;
$b = 30;
$c = '20';

if ( $a > $ b) {
   echo '$a is greater than $b'; #example of major, types not taken into account
} #in this case it will not show the message because it is false
if ( $a > $ c) {
   echo '$a is greater than $c'; #example of major, types not taken into account
} #in this case it will not show the message because it is false
if ( $a < $ b) {
   echo '$a is less than $b'; #example of minor, types not taken into account
} #in this case it will show the message for being true
if ( $a < $ c) {
   echo '$a is less than $c'; #example of minor, types not taken into account
} #in this case it will show the message for being true
if ( $a >= $ b) {
   echo '$a is greater than or equal to $b'; #example of greater or equal, the types are not taken into account
} #in this case it will not show the message because it is false
if ( $a >= $ c) {
   echo '$a is greater than or equal to $c'; #example of greater or equal, the types are not taken into account
} #in this case it will not show the message because it is false
if ( $a <= $ b) {
   echo '$a is less than or equal to $b'; #example of less than or equal, types are not taken into account
} #in this case it will not show the message because it is false
if ( $a <= $ c) {
   echo '$a is less than or equal to $c'; #example of less than or equal, types are not taken into account
} #in this case it will not show the message because it is false
if ( $a != $ b) {
   echo '$a is different than $b'; #example of different, types are not taken into account
} #in this case it will show the message for being true
if ( $a != $ c) {
   echo '$ a is different than $ c'; #example of different, types are not taken into account
} #in this case it will show the message for being true
if ( $a <> $ b) {
   cho '$a is different than $b'; #example of different, types are not taken into account
} #in this case it will show the message for being true
if ( $a <> $ c) {
   echo '$a is different than $c'; #example of different, types are not taken into account
} #in this case it will show the message for being true
if ( $a ! = = $ b) {
   echo '$a is different than $b'; #example of different, types are taken into account
} #in this case it will show the message for being true and of the same type
if ( $a ! = = $ c) {
   echo '$a is different than $c'; #example of different, types are taken into account
} #in this case it will not show the message because it is true and of different types
if ( $a == $ b) {
   echo '$a is the same as $b'; #example example, the types are not taken into account
} #in this case it will not show the message because it is false
if ( $a == $ c) {
   echo '$a is the same as $c'; #example example, the types are not taken into account
} #in this case it will not show the message because it is false
if ( $a = = = $ b) {
   echo '$a is the same as $b'; #example example, types are taken into account
} #in this case it will not display the message because it is false and of the same type
if ( $a = = = $ c) {
   echo '$a is the same as $c'; #example example, types are taken into account
} #in this case it will not display the message because it is false and of different types
switch ($a <=> $b) { #Order comparison example, types are taken into account
    case -1:
        echo '$a is less than or equal to $b';
        break;
    case 0:
        echo '$a is equal to $b';
        break;
    case 1:
        echo '$a is greater than $b';
        break;
} # in this case the message of -1 will be displayed as a less than b and of the same type
#in case of being of different type it will return a value other than 0

#We want to get the value of the variable $_GET ['user'] and we will return 'nobody' if it does not exist
$username = $_GET['user'] ?? 'no one';
#Thanks to the operator ?? We have the operation equivalent to:
$username = isset( $_ GET ['user'] ) ? $_GET['user'] : 'nobody';
#which allows us to save code

#We can also use it in a chain, which will return the first value defined in $_GET['user'], $_POST['user'] and 'nobody'
$username = $_GET['user'] ?? $_POST['user'] ?? 'no one';

Logical operators

The logical operands is related to the relational as they are normally the operands used are the result of expressions in relational

The resulting values are boolean

Logical operators
AND	True if both are true
& &	It is equivalent to AND
OR	True if one of them is true
\| \|	It's equivalent to OR
XOR	True if one of them is true, but not both
!	If it was true it goes to false and vice versa

$a = true;
$b = false;

if ($a AND $b) {
    echo '$a and $b are both true';
} else {
    echo '$a or $b are false, or both are false';
}
if ($a && $b) {
    echo '$a and $b are both true';
} else {
    echo '$a or $b are false, or both are false';
}
if ($a OR $b) {
    echo '$a or $b are true, or both are true';
} else {
    echo 'Both are false';
}
if ($a || $b) {
   echo '$a or $b are true, or both are true';
} else {
    echo 'Both are false';
}
if ($a XOR $b) {
    echo '$a or $b are true, but both are not true';
} else {
    echo 'Both are false or both are true';
}
if (!$a) {
    echo 'It was false';
} else {
    echo 'It was true'; # will show this value, because before applying the operator was true
}

Bitwise operators

The way of working of these operators is to convert to the binary operands and then operate with them bitwise

Bitwise operators
&	AND
\|	OR
^	XOR
~	NOT
<<	Propagation to the left Shift the value to the left by entering zeros, if it goes out of range, values are lost
>>	Spread to the right Moves the value to the right entering by the left, the sign bit and eliminating the values that are out by the right

Note Propagation operators take two operands: the first is the variable to propagate and the second is the number of positions to propagate

$a = 0100;
$b = 0101;

$c = $a & b; #AND example
echo $c; #will return the value 0100

$c = $a | b; #OR example
echo $c; #will return the value 0101

$c = $a ^ b; #XOR example
echo $c; #will return the value 0001

$a = 4;
$b = 1;

$c = $a << b; #left propagation example
echo $c; #will return the value 8 which in binary is 00000000000000000000000000001000

$c = $a >> b; #right propagation example
echo $c; #will return the value 2 which in binary is 00000000000000000000000000000010

$a = -4;
$b = 1;

$c = $a << b; #example of propagation to the left of a negative number
echo $c; #will return the value -8 which in binary is 11111111111111111111111111111000

$c = $a >> b; #example of propagation to the right of a negative number
echo $c; #will return the value -2‬ which in binary is 11111111111111111111111111111100

Assignment operators

The assignment is also an operator that returns the variable modified

The assignment operator in PHP is =

The assignment operators shown below are but abbreviations that make expressions more comfortable and simple, even if they are sometimes more unreadable

Assignment operators
Operator	Expression	Equivalence
=	$A = $B = $C; $D = ‘Text’;	$A = $C; $B = $C; $D = ‘Text’;
+ =	$A + = 4;	$A = $A + 4;
– =	$A – = 3 * $B;	$A = $A – (3 * $B);
* =	$A * = 2;	$A = $A * 2;
/ =	$A / = 35 + $B;	$A = $A / (35 + $B);
% =	$A % = $B;	$A = $A % $B;
. =	$D . = ‘ of test’;	$D = $D . ‘ of test’;
>> =	$A >> = 1;	$A = $A >> 1;
<< =	$A << = $B;	$A = $A << $B;
& =	$A & = ($C + = 3);	$C = $C +3; $A = $A & $C;
^ =	$A ^ = 2;	$A = $A ^ 2;
\| =	$A \| = $C;	$A = $A \| $C;

Other operators

Selection operator

This operator is used to execute an operation or another depending on the condition

The format is as follows:

Condition ? Exp1 : Exp2

If the condition is met it evaluates and returns the expression Exp1 if not the Exp2

We can put a just value

Example:

$x = 5;
$y = 1;
$k = 0;

$i = ($x != $y) ? 6 : $k++;
echo $ i; #in this example $i will return the value 6

New operator

This operator is used to create an instance of a type of objects previously defined

The syntax to follow is as follows:

variableObject = new ObjectType(parameter1, parameter2, ...);

These parameters are passed to the constructor of that object in question

Operador clone

This operator will be used to create a copy of a previously defined object (which invokes, if possible, the method __clone() object)

The syntax to follow is as follows:

variableObject = clone ObjectType;

When cloning an object, PHP will make a shallow copy of the object's properties

Properties that are references to other variables will keep the references

Once cloning is complete, the method will be called __clone() of the new object (if the method __clone() defined), to allow you to make the necessary changes to your properties

gettype operator

This operator applied to a variable returns the type of object to which belongs the data contained by that variable

Its syntax is:

gettype(variable);

The values you can return are:

boolean
integer
double

For historical reasons it is returned double also when it's kind of float
string
array
object
resource
NULL
unknown type

Preference

The operator precedence will determine the order in which they are running in a given expression

Using parentheses will check that the operations are carried out according to us we want to

In PHP the preference of the operators from highest to lowest is as follows:

Preference

Other operators

clone

new

Array

[

]

Exponentiation

(in / de) crease /types

– –

(int)

(float)

(string)

(array)

(object)

(bool)

Other operators

gettype

Denial

Mul / Div / Rest

Addition / Subtraction

–

Spread

Relational

< =

> =

Equality

= =

= = =

! = =

< >

< = >

Bitwise AND

Bitwise XOR

Bitwise OR

AND logic

A logical OR

| |

Equality

? ?

Other operators

Assignment

+ =

– =

* =

* * =

/ =

. =

% =

& =

| =

^ =

>> =

<< =

AND logic

AND

XOR lógica

XOR

A logical OR

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Secarcam's Computer Science Web

PHP operators

PHP operators

Arithmetic operators

Operators of increase (++) and decrease (- -)

Relational operators

Logical operators

Bitwise operators

Assignment operators

Other operators

Selection operator

New operator

Operador clone

gettype operator

Preference

Web page of Sergio Cárcamo Garcia dedicated to the computing and related topics such as programming languages, statistics, mathematics, etc

PHP operators

Arithmetic operators

Operators of increase (++) and decrease (- -)

Relational operators

Logical operators

Bitwise operators

Assignment operators

Other operators

Selection operator

New operator

Operador clone

gettype operator

Preference

Web page of Sergio Cárcamo Garcia dedicated to the computing and related topics such as programming languages, statistics, mathematics, etc

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