171 lines
2.5 KiB
Markdown
171 lines
2.5 KiB
Markdown
---
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title: Loop
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---
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# PHP Loop
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When you need to repeat same task for many times, you can use loop instead of keep adding same code over and over again.
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In PHP you have the following loop statements :
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- for - loop through a block of code with specific number of times.
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- while - loop through a block of code if condition is true.
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- do...while - loop through a block of code one and continue loop if condition is true.
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- foreach - loop through a block of code for each value within an array.
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Using a `break` within the loop can stop the loop execution.
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# For loop
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Loop through a block of code with specific number of times.
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## Syntax
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```php
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for (init counter; condition; counter increment or decrement)
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{
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// Code to be executed
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}
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```
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## Example
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```php
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<?php
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for($index = 0; $index < 5; $index ++)
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{
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echo "Current loop counter ".$index.".\n";
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}
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?>
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```
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## Output
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```
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> Current loop counter 0.
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> Current loop counter 1.
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> Current loop counter 2.
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> Current loop counter 3.
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> Current loop counter 4.
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```
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# While loop
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Loop through a block of code if condition is true.
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## Syntax
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```php
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while (condition)
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{
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// Code to be executed
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}
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```
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## Example
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```php
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<?php
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$index = 10;
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while ($index >= 0)
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{
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echo "The index is ".$index.".\n";
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$index--;
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}
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?>
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```
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## Output
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```
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> The index is 10.
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> The index is 9.
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> The index is 8.
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> The index is 7.
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> The index is 6.
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> The index is 5.
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> The index is 4.
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> The index is 3.
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> The index is 2.
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> The index is 1.
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> The index is 0.
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```
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# Do...While loop
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Loop through a block of code one and continue loop if condition is true.
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## Syntax
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```php
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do
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{
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// Code to be executed
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}
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while (condition);
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```
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## Example
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```php
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<?php
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$index = 3;
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do
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{
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// execute this at least 1 time
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echo "Index: ".$index.".\n";
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$index --;
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}
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while ($index > 0);
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?>
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```
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## Output
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```
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> Index: 3.
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> Index: 2.
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> Index: 1.
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```
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# Foreach loop
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Loop through a block of code for each value within an array.
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## Syntax
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```php
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foreach ($array as $value)
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{
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// Code to be executed
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}
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```
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## Example
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```php
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<?php
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$array = ["Ali", "Ah Kao", "Muthu", "Gwen", "Lucida", "Cecily", "Arthur", "Flora"];
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foreach ($array as $name)
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{
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echo "Hi, my name is ".$name.".\n";
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if ($name == "Cecily")
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{
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echo "\"Hello, ".$name."!\"";
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// stop the loop if name is Cecily
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break;
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}
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}
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?>
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```
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## Output
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```
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> Hi, my name is Ali.
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> Hi, my name is Ah Kao.
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> Hi, my name is Muthu.
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> Hi, my name is Gwen.
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> Hi, my name is Lucida.
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> Hi, my name is Cecily.
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> "Hello, Cecily!"
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```
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