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Operators

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Operators are used to manipulate or perform operations on variables and values.

Many operators are used in PHP, such as:-.

Assignment Operators
Arithmetic Operators
Comparison Operators
String Operators
Combination Arithmetic & Assignment Operators

Assignment Operators

They are used to set a variable equal to a value or set a variable to another variable's value.

Such an assignment of value is done with the "=", or equal character. Example:

$my_variable = 18;
$another_variable = $my_variable

Now both $my_variable and $another_variable contain the value 18. Assignments can also be used in conjunction with arithmetic operators.

Arithmetic Operators

Operator	English	Example
+	Addition	2 + 4
-	Subtraction	6 - 2
*	Multiplication	5 * 3
/	Division	15 / 3
%	Modulus	43 % 10

PHP Code:

<?php

$addition = 2 + 4;
$subtraction = 6 - 2;
$multiplication = 5 * 3;
$division = 15 / 3;
$modulus = 5 % 2;

echo "Perform addition: 2 + 4 = ".$addition;
echo "Perform subtraction: 6 - 2 = ".$subtraction;
echo "Perform multiplication: 5 * 3 = ".$multiplication;
echo "Perform division: 15 / 3 = ".$division;
echo "Perform modulus: 5 % 2 = " . $modulus . "[ Modulus is the remainder after the division operation has been performed.In this case it was 5 / 2, which has a remainder of 1].";

?>

Display:

Perform addition: 2 + 4 = 6
Perform subtraction: 6 - 2 = 4
Perform multiplication: 5 * 3 = 15
Perform division: 15 / 3 = 5
Perform modulus: 5 % 2 = 1 [Modulus is the remainder after the division operation has been performed. In this case it was 5 / 2, which has a remainder of 1.]

Comparison Operators

Comparison operators are used to check the relationship between variables and/or values.

Comparison operators are used inside conditional statements and evaluate to either true or false.

Important comparison operators of PHP are:-

Operator	English	Example	Result
==	Equal To	$x == $y	false
!=	Not Equal To	$x != $y	true
<	Less Than	$x < $y	true
>	Greater Than	$x > $y	false
<=	Less Than or Equal To	$x <= $y	true
>=	Greater Than or Equal To	$x >= $y	false

String Operators

There is only one string operator. ["." the period]

It is used to add two strings together, or more technically, the period is the concatenation operator for strings.

PHP Code:

<?php

$x_string = "Hello";
$y_string = " Cindy";
$output_string = $x_string . $y_string;

echo $output_string . "!";

?>

Display:

Hello Cindy!

Combination Arithmetic & Assignment Operators

In programming, various increasing or decreasing counters are used.

Say you want a counter that increase by 1,

$number = $number + 1;

However, there is a shorthand for doing this.[combination assignment/arithmetic operator that would accomplish the same task]

$number += 1;

Here are some examples of other common shorthand operators. In general, "+=" and "-=" are the most widely used combination operators.

Operator	English	Example	Equivalent Operation
+=	Plus Equals	$x += 2;	$x = $x + 2;
-=	Minus Equals	$x -= 4;	$x = $x - 4;
*=	Multiply Equals	$x *= 3;	$x = $x * 3;
/=	Divide Equals	$x /= 2;	$x = $x / 2;
%=	Modulo Equals	$x %= 5;	$x = $x % 5;
.=	Concatenate Equals	$my_str.= "hello";	$my_str = $my_str . "hello";

Pre/Post-Increment & Pre/Post-Decrement

There is an even shorter way for adding 1 or subtracting 1 from a variable.

To add one to a variable or "increment" use the "++" operator:

$x++;

Which is equivalent to $x += 1; or $x = $x + 1;

To subtract 1 from a variable, or "decrement" use the "--" operator:

$x--;

Which is equivalent to $x -= 1; or $x = $x - 1;

In addition to this you can specify whether you want the increment to be:-

Before code is being executed.
After the line has executed.

Example code below will display the difference.

PHP Code:

<?php

$x = 4;
echo "The value of x with post-plusplus = " . $x++;
echo "The value of x after the post-plusplus is " . $x;

$x = 4;
echo "The value of x with with pre-plusplus = " . ++$x;
echo "The value of x after the pre-plusplus is " . $x;

?>

Display:

The value of x with post-plusplus = 4
The value of x after the post-plusplus is = 5
The value of x with with pre-plusplus = 5
The value of x after the pre-plusplus is = 5

The value of $x++ is not reflected in the echoed text because the variable is not incremented until after the line of code is executed.

But, with the pre-increment "++$x" the variable does reflect the addition immediately.

Note
For more detail please see Php Manual at http://www.php.net

Variable မ်ားႏွင့္ တန္ဖိုးမ်ား (values) အား ျပဳျပင္ ေျပာင္းလဲ ရန္ operator မ်ားကို အသံုးျပဳ သည္။

Php တြင္ operator အမ်ားအျပား အသံုးျပဳ ပါသည္။ အမ်ိဳးအစား အခ်ိဳ႔ ကို ေအာက္တြင္ ေဖၚျပအပ္ ပါသည္။

Assignment Operators
Arithmetic Operators
Comparison Operators
String Operators
Combination Arithmetic & Assignment Operators

Assignment Operators

Assignment operator မ်ားကို variable တစ္ခုအား တန္ဖိုးသတ္မွတ္ (set) လုပ္ရန္ ႏွင့္ variable မ်ားအား အျခား variable တန္ဖိုးျဖင့္ set လုပ္သည့္ အခါမ်ား တြင္ အသံုးျပဳ ပါသည္။

တန္ဖိုး မ်ားကို assign (set) လုပ္ရာ တြင္ "=" ညီမွ်ျခင္ (equal) သကၤတ ကိုအသံုးျပဳ ပါသည္။ ဥပမာ :-

$my_variable = 18;
$another_variable = $my_variable

ယခု $my_variable ႏွင့္ $another_variable တိ္ု႔၏ တန္ဖိုး သည္ 18 ျဖစ္ေန ပါၿပီး။ Assignment operators မ်ားကို arithmetic (သခ်ၤာ) operators မ်ားႏွင့္ လည္း တြဲဖက္ အသံုးျပဳ ႏိုင္ ပါသည္။

Arithmetic (သခ်ၤာ) Operators

Operator	English	Example
+	Addition	2 + 4
-	Subtraction	6 - 2
*	Multiplication	5 * 3
/	Division	15 / 3
%	Modulus	43 % 10

PHP Code:

Display:

Comparison (ႏွိဳင္းယွဥ္) Operators

Comparison operator မ်ားကို variable အခ်င္းခ်င္း ေသာ္၎၊ variable ႏွင့္ တန္ဖိုး (value) တို႔ကို စစ္ေဆး ႏိုင္းယွဥ္ ရာတြင္ အသံုးျပဳ ပါသည္။

Comparison operators မ်ားကို conditional statements ႏွင့္တြဲဖက္ ၿပီး true or false ဟုတ္မဟုတ္ အေျဖထုတ္၍ လည္းသံုးေလ့ ရွိ ပါသည္။

Php ၏ အေရးႀကီးေသာ comparison operator မ်ားကို ေအာက္တြင္ ေဖၚျပ အပ္ပါသည္။

Operator	English	Example	Result
==	Equal To	$x == $y	false
!=	Not Equal To	$x != $y	true
<	Less Than	$x < $y	true
>	Greater Than	$x > $y	false
<=	Less Than or Equal To	$x <= $y	true
>=	Greater Than or Equal To	$x >= $y	false

String Operators

String operator တစ္ခုသာ ရွိပါသည္။ ["." the period]

၎ operator ကို strings ႏွစ္ခုအား ဆက္ရာတြင္ အသံုးျပဳ သည္။ အဆိုပါ period အား concatenation operator ဟုလည္း ေခၚသည္။

PHP Code:

<?php

$x_string = "Hello";
$y_string = " Cindy";
$output_string = $x_string . $y_string;

echo $output_string . "!";

?>

Display:

Hello Cindy!

သခ်ၤာ (Arithmetic) ႏွင့္ Assignment Operators တို႔အား တြဲဖက္ အသံုး ျပဳျခင္း။

Program မ်ားေရး ရာတြင္ တေျဖးေျဖး ႀကီးသြားေသာ သို႔မဟုတ္ တေျဖးေျဖး ငယ္သြားေသာ counter မ်ားကို သံုးေလ့ ရွိ ပါသည္။

တစ္ႀကိမ္လ်င္ ၁ တိုးသြားေသာ counter တခု ဖန္တည္းရန္ ေအာက္ပါ အတိုင္း ေရးသား ႏိုင္ ပါသည္။

$number = $number + 1;

Assignment ႏွင့္ arithmetic operator ႏွစ္ခု ကိုတြဲဖက္ အသံုး ျပဳၿပီး ေအာက္ပါ အတိုင္း အတိုေကာက္ ေရး၍ လည္းရ ပါသည္။

$number += 1;

ေအာက္ပါ ဇယားတြင္ အတိုေကာက္ ေရးတားေသာ နမူနာ အခ်ိဳ႔ကို ေဖၚျပထား ပါသည္။ အမ်ား အာျဖင့္ "+=" and "-=" တို႔မွာ အသံုး မ်ားေသာ တြဲဖက္ သေကၤတ မ်ား ျဖစ္ၾက ပါသည္။.

Operator	English	Example	Equivalent Operation
+=	Plus Equals	$x += 2;	$x = $x + 2;
-=	Minus Equals	$x -= 4;	$x = $x - 4;
*=	Multiply Equals	$x *= 3;	$x = $x * 3;
/=	Divide Equals	$x /= 2;	$x = $x / 2;
%=	Modulo Equals	$x %= 5;	$x = $x % 5;
.=	Concatenate Equals	$my_str.= "hello";	$my_str = $my_str . "hello";

Pre/Post-Increment & Pre/Post-Decrement

အထက္ေဖၚျပပါ ဇယား ထက္ပင္ တိုတုတ္ ေသာ ေရးသားနည္း မ်ားရွိပါ ေသးသည္။.

Variable တခုသ႔ို ၁ ေပါင္းထည့္ ရန္ "++" operator ကိုသံုးႏိုင္ ပါသည္။

$x++;

Which is equivalent to $x += 1; or $x = $x + 1;

Variable တခုမွ ၁ ႏွဳတ္ရန္ "--" operator ကိုသံုးႏိုင္ ပါ သည္။

$x--;

Which is equivalent to $x -= 1; or $x = $x - 1;

ထို႔ျပင္ အတိုး အေလွ်ာ့ ကို မည္သည့္ အခ်ိန္တြင္ ျပဳလုပ္ မညိကို လည္းသတ္မွတ္ ေပးႏိုင္ ပါ ေသးသညိ။

Code ကို execute မလုပ္မွီ အတိုး/အေလွ်ာ့ လုပ္ျခင္။
Code ကို execute လုပ္ၿပီးမွ အတိုး/အေလွ်ာ့ လုပ္ျခင္။

ေအာက္ ေဖၚျပပါ ဥပမာမ်ား တြင္ အတိုး/အေလွ်ာ့ လုပ္ပံု ႏွစ္မ်ိဳး ကိုေလ့လာ ႏိုင္ ပါသည္။

PHP Code:

Display:

The value of x with post-plusplus = 4
The value of x after the post-plusplus is = 5
The value of x with with pre-plusplus = 5
The value of x after the pre-plusplus is = 5

ပထမ code စာေၾကာင္းတြင္ post-increment "$x++" ကို execute မလုပ္ ေသးသျဖင့္ ရလာဘ္ မွာ ၄ ျဖစ္ ပါသည္။

သို႔ေသာ္ ေနာက္ code စာေၾကာင္းမွာ pre-increment "++$x" ကို execute လုပ္ၿပီး ျဖစ္သျဖင့္ ရလာဘ္ မွာ ၅ ျဖစ္ ပါသည္။

Note
For more detail please see Php Manual at http://www.php.net