PHP-Loop

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<Beginner PHP><Array><Loop><Function><Pre-Def variable><Session><Read Write File><CRUD>

<Advanced PHP><PHP MySQL PHP MyAdmin><PHP MySQL Notes>

 

While Loop

execute as long as condition is true

while (condition is true){

code

};

Exemple

$i=1

while ($i<7){ // first check if $i<7 is true  - $ = 1 so it is true

echo "value is $i <br />"; 

$i++; // add + 1 to $i = so make it 2 - and loop

}

//1,2,3,4,5,6

Do while Loop

The condition is tested after executing the statement (TR: yani illa bir kez işlem yapılıyor)

The loop executes at least once

$i=5;

do{

echo"Number is".$i."<br />"; // do not make any check - write directly this 

$i++; // then add +1 to $i = make it 2

} while ($i<=7); // $i is now 2 so loop again

//1,2,3,4,5,6,7

For Loop

When you know in advance how many times the script should run

for (init;test;increment){

code

}

init : initialize counter

test: evaluate

• true: continue
• false: end

increment: increase counter

Note:

if condition is not true it outpiuts nothing

for ($a=0;$a<6;$a++){

echo "value of a: ".$a."<br />;

}

For each Loop

It works only on arrays. It loops through each key/value pair

To output value

foreach(array as $value){

code

}

To output key and value

foreach(array as $key=>value){

code

}

Exemple

$names=array("John","David","Amy");

foreach($names as $name){

echo $name."<br />";

}

Switch and Break Statements 

This is alternative = if else if else

Switch (n){

case value 1:

code;

case value 2:

code;

break;

default: // optional

}

Exemple

$today=`Monday`;

switch($today){

case "Monday";

break;

case "Tuesday";

break;

default:

echo "invalid day";

}

Continue statement

Allows skipping over of what remains of the current loop iteration

Exemple

Skip even numbers

for($i=0;$i<10;$i++){

    if($i%2==){

    continue;

    }

echo $i." number,";

}

Skip numbers 10 and 14

for($i=0;$i<=15;$i++){

    if ($i==10 || $i==14){ // either x or y is true

    continue;

    }

echo $i."<br />";

}