PHP Return Loop Result | 易学教程

问题

I am new to the world of coding as well as PHP and am wondering how I can use return when looping. For example I would like to return/display 1-10 however not use echo.

$start = 1;
$end = 11;

for($start; $start < $end; $start=$start+1) {

echo $start; //how can I use return?

}

回答1:

Well, return will exit the function, so if you put return in a loop, the loop will only do one iteration (until the return statement).

You can collect all the values in an array and return the array:

function myFunction() {
    $start = 1;
    $end = 11;
    $values = array();

    for($start; $start < $end; $start=$start+1) {
       $values[] = $start;
    }

    return $values;
}

That said, a function generating consecutive numbers already exists: range().

回答2:

return is for sending the results of a function call back to the function or script that called it. It's the opposite of passing parameters to a function.

What you're doing is looping over a variable in the same scope, so return is not needed. Printing is done via echo or print. However, you may choose to build a value in that loop and print that once the loop is completed.

Additionally, if you're in a loop and you want to stop that loop immediately, use break; and if you want to skip the iteration you're on and go to the next one, use continue.

Here's some additional reading.

More clarification on continue. Say, for whatever reason, we don't want to do anything when $i is 6:

$start = 1;
$end = 11;

for ($i = $start; $i < $end; $i++) 
// changed this to iterate over $i for readability/clarity
{
    if ($start == 6)
    {
        // essentially, continue just skips this iteration of 
        // the loop, goes back to the top, iterates $i based on 
        // that third parameter in the for() declaration, and 
        // continues on.

        continue;
    }


    echo $start; //how can I use return?
}

// output: 1234578910

回答3:

just use

function foobar()
{   
   $output = '';
   for ( $i = 1 ; $i <= 10 ; $i++ )
   {
      $output .= $i;
   }
   return $output
}

echo foobar();

回答4:

You can achieve it by defining a variable you want to return inside and outside the loop with .=.

Here is a working example:

function my_function() {

// I am the variable to be return-ed
$k = "My World<br/>";

for ($z=1; $z<=3; $z++) {
$v = 'Here'.$z;

// I am the same variable but I am going inside the loop
$k .= $v . "<br/>";
}

//I am not always important to be here!
$k .= "Is Awesome";

// This is the show time..
return $k;

} 

my_function();

Output:

My World
Here1
Here2
Here3
Is Awesome

回答5:

Return will end the function that you are currently in. The scenario you have given us is not a good scenario to use the return function.

The example below will do the same as your code, but uses a function as well as your for loop. Hope this answeres your question.

$start = 11;
$end = 20;

for($start; $start <= $end; $start++){
     echo calculateValue($start);
}

function calculateValue($value){
    return $value - 10;
}

回答6:

 function loop_kec($ar_kec) {
        $total_data = count($ar_kec) - 1;
        //$return_kec = array();
        for ($e = 0; $e < $total_data; $e++) {
            $return_kec .= 'kecamatan = ' . "'$ar_kec[$e]'" . ' or ';
        }
        $return_kec .= 'kecamatan = ' . "'$ar_kec[$total_data]'";
        return $return_kec;
    }

来源：https://stackoverflow.com/questions/5890944/php-return-loop-result

标签

php

loops

return