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PHP

Posted by Kristian Woods
Kristian Woods
23,414 Points

Can someone clear up the PHP forloop in conjunction with associative arrays?

Hey, I'm retracing my steps in PHP because I'm rusty. My problem is with understanding associative arrays with the forloop.

for example:

<?php

  $myArray = array("one", "two", "three");

  foreach($myArray as $value) {
      echo $value . "<br>";
  }

?>

I know this loops through $myArray and assigns each element to $value

<?php

  $myArray = array("one", "two", "three");

  foreach($myArray as $key => $value) {
      echo $key . " " .  $value . "<br>";
  }

?>

I also know that by including the $key variable, you now have access to the key/index associated with that element.

What I don't understand is this:

 <?php

  $myArray[0] = ["red" => "stop"];
  $myArray[1] = ["green" => "go"];


  foreach($myArray as $key => $value) {
      echo $key . "<br>";
  }

?>

My thinking was that the $key would be "red" and "green" - as they are the key to the values - "stop" and "go"

so, just to be clear - the first associative-array ["red" => "stop"], would be at index position 0 in $myArray and ["green" => "go"], would be at index 1? And in order to get the key in those internal arrays, would be to do another foreach loop inside the existing forloop?

<?php

  $myarray[] = array ("blue" => "cold");
  $myarray[] = array ("red" => "hot");

foreach($myarray as $key => $value) {
  echo $key . $value .  "<br>";
  foreach($value as $innerkey => $innerValue) {
    echo $innerkey . "=> " . $innerValue . "<br>";
  }



}

?>

Thank You for any help

Dmitriy Davydov
Dmitriy Davydov
8,768 Points

Hey Kristian! Within the first (outer) loop you can't impress $value with echo() becase that is an array. I changed a little bit your code so it works now : <?php

$myarray[] = array ("blue" => "cold"); $myarray[] = array ("red" => "hot");

foreach($myarray as $key => $value) { echo $key . " : "; foreach($value as $innerkey => $innerValue) { echo $innerkey . "=> " . $innerValue . "<br>"; } }

?>

1 Answer

Darrell Conklin
seal-mask
.a{fill-rule:evenodd;}techdegree
Darrell Conklin
Python Development Techdegree Student 22,377 Points
Darrell Conklin
.a{fill-rule:evenodd;}techdegree
Darrell Conklin
Python Development Techdegree Student 22,377 Points

A secondary foreach loop is one way to handle iterating through multidimensional arrays. However depending on your circumstances there is always another way to accomplish what you want to do. You don't need to echo out the variable after instantiating it within the foreach loop, just pass it to the next loop like such.

<?php 

$myArray[0] = ["red" => "stop"];
$myArray[1] = ["green" => "go"];

foreach ($myArray as $key => $value) {
  foreach ($value as $innerKey => $innerValue) {
    echo $innerKey . "<br>";
  }
}

or you could do something like this

<?php

$myArray[0] = ["red" => "stop"];
$myArray[1] = ["green" => "go"];

foreach ($myArray as $key => $value) {
  echo key($value) . '<br>';
}

Another way to get your inner values.

<?php

$myArray[0] = ["red" => "stop"];
$myArray[1] = ["green" => "go"];

for ($i = 0; $i < count($myArray); $i++) {
  foreach ($myArray[$i] as $key => $value) {
      echo $key . " = " . $value . "<br>";
  }
}

If the keys in the inner arrays were the same you could do something like this:

<?php

$myArray[0] = [
  "color" => "red",
  "action" => "stop"
];
$myArray[1] = [
  "color" => "green",
  "action" => "go"
];

foreach ($myArray as $innerArray) {
  echo $innerArray['color'] . " = ". $innerArray['action'] . "<br>";
}

but the main idea is that a foreach loop can only iterate over one array at a time. The $key variable holding the initial key and the $value holding the associated value of the key, in this case, another array. Getting the keys and values within the inner array can be done in many different ways.