PHP using array(?) to concatenate argument string?

Question

Sorry for not using the right terminology, but given how basic my PHP level is, perhaps you will not mind so much.

A function for a plugin I am using allows arguments in order to selectively echo content:

<?php phpquote(argumentstring); ?>

An example of the argument string is e.g. auto_refresh=0&tags=a,b,c

I had always assumed it would be possible to use an array to build up a 'string' e.g. something like

<?php $arg=array( 'auto_refresh' => '0', 'tags' => 'a,b,c' );
phpquote($arg); ?>

And was therefore thinking I could bring in other content from another field e.g.

<?php 
$fieldcontent = get_field("field_content");
$arg=array( 'auto_refresh' => '0', 'tags' => $fieldcontent );
phpquote($arg); ?>

However, this does not seem to work and so my two questions are:

1. Is it possible to use an array to build such an argument string? Or does this depend on the plugin?
2. If so, is it possible to bring in content from elsewhere as the example above?

Thanks in advance. I appreciate this may seem like a really basic question with incorrect terminology (sorry!) so hope it makes sense to the experts.

Answer 1

You can use implode() and array_map() PHP functions to make an array to become an argument string:

<?php

    $args = array( 'auto_refresh' => '0', 'tags' => 'a,b,c' );

    function rb_map( $a, $b ) {
        return $a . '=' . $b;
    }

    $arg_string = implode('&', array_map( 'rb_map', array_keys($args), $args ) );
    //var_dump($arg_string);
?>

Answer 2

Loop through the array and use the implode() function for glueing pieces together. manual

Or you can do something like this, too:

$argumentString= "";
foreach($arg as $k=>$v){
    $argumentString.= $k.'='.$v.'&';
}
$argumentString = substr($argumentString,0,-1); //removes the last &

Answer 3

<?php
$arg=array( 'auto_refresh' => '0', 'tags' => 'a,b,c' );
echo urldecode(http_build_query($arg)); //output: auto_refresh=0&tags=a,b,c
?>

Is this what you want?

Check http_build_query for more information

Answer 4

Whether or not you can use an array as the argument of a function depends on how that is defined / used in the function itself.

Consider this for example:

function test($var) {
    print_r($var);
}

$bla = array(1 => "test me", 2 => "balbla");

test($bla);

(You can play with it here)

You can pass either a string or an array as an argument of the test function as print_r is able to handle both. If the function had echo for example, and you passed an array to the function as argument, it would fail.