Comparative explanation of For, While, and Foreach in php

In the process of using PHP as a programming language, we often encounter situations where we need to execute a piece of code multiple times. At this time, you need to use PHP loop. PHP provides three different types of loops for you to use in appropriate scenarios:

• For loop

• While loop

• Foreach Loop

For loop

for loop is used to determine whether you How many times the expression needs to be executed.

Syntax:

for (initialization; condition; increment)
{
    code to be executed;
}

<?php
for($i=1; $i<=100000; $i++)
{    
   echo "The number is " . $i . "<br>";
}
?>

While loop

The while expression will execute a section of code until the conditional statement is false. While loops are generally better suited for database related operations.

Syntax:

while (condition)
{
    code to be executed;
}

<?php
// If you had an array with fruit names and prices in you could use foreach
$fruit = array( 
    "orange" =--> "5.00", 
    "apple" => "2.50", 
    "banana" => "3.99" 
); 

foreach ($fruit as $key => $value) 
{ 
 "$key is $value dollars";
} 
?>

Comparison of three types of loops

We know that there are many kinds of loops in PHP, and now we need to know which loop is more efficient so that The apps we write are faster.

Let’s start the experiment for comparison.

While loop vs. For loop

<?php    
// While Loop    
$a=0;    
     while($a < 1000)
    {
        $a++;
    }
?>

VS.

<?php    
  // For Loop    
    for($a = 0; $a < 1000;)
    {
     $a++;
    }
?>

The above experiment proves that the While loop performs better than the For loop The efficiency is 19.71% higher. Therefore, it is recommended to use while loops instead of For loops whenever possible.

For loop vs Foreach loop

<?php    
  $test = array(1 => "cat", "dog" => 0, "red" => "green", 5 => 4, 3, "me");    
  $keys = array_keys($test);    
  $size = sizeOf($keys);    
  for($a = 0; $a < $size; $a++)
 {        
    $t = $test[$keys[$a]];
  }
?>

VS.

<?php    
  $test = array(1 => "cat", "dog" => 0, "red" => "green", 5 => 4, 3, "me");    
  foreach($test as $t)
  {
    
 }
?>

The above experiment proves that the Foreach loop is 141.29% faster than the For loop!

Conclusion

These loops are usually used to achieve different purposes. Now we know how each loop performs in terms of execution efficiency. When execution efficiency needs to be pursued, we usually recommend using while loops instead of for loops. Similarly, between the foreach loop and the loop loop, use the foreach loop as much as possible. Next, we'll look at how to effectively use loops in templates. Please stay tuned.

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