help with php array's

[BrentonHale]

I'm getting the following error messages with the code below:

 

Notice:  Undefined variable: state_totals in C:\wamp\www\chapter4_exercises_arrays.php on line 22Notice:  Undefined index: NY in C:\wamp\www\chapter4_exercises_arrays.php on line 22Notice:  Undefined index: CA in C:\wamp\www\chapter4_exercises_arrays.php on line 22Notice:  Undefined index: IL in C:\wamp\www\chapter4_exercises_arrays.php on line 22Notice:  Undefined index: TX in C:\wamp\www\chapter4_exercises_arrays.php on line 22Notice:  Undefined index: PA in C:\wamp\www\chapter4_exercises_arrays.php on line 22Notice:  Undefined index: AZ in C:\wamp\www\chapter4_exercises_arrays.php on line 22Notice:  Undefined index: MI in C:\wamp\www\chapter4_exercises_arrays.php on line 22

 

 

 

<?php
// Separate the city and state name in the array so we can total by state
$population = array('New York' => array('state' => 'NY', 'pop' => 8008278),
'Los Angeles' => array('state' => 'CA', 'pop' => 3694820), 
'Chicago' => array('state' => 'IL', 'pop' => 2896016),
'Houston' => array('state' => 'TX', 'pop' => 1953631),
'Philadelphia' => array('state' => 'PA', 'pop' => 1517550),
'Phoenix' => array('state' => 'AZ', 'pop' => 1321045),
'San Diego' => array('state' => 'CA', 'pop' => 1223400),
'Dallas' => array('state' => 'TX', 'pop' => 1188580),
'San Antonio' => array('state' => 'TX', 'pop' => 1144646),
'Detroit' => array('state' => 'MI', 'pop' => 951270));
// Use the $state_totals array to keep track of pre-state totals $state_totals = array();
$total_population = 0; 
print "<table><tr><th>City</th><th>Population</th></tr>\n";
foreach ($population as $city => $info) {
// $info is an array with two elements: pop (city population)
// and state (state_name)
$total_population += $info['pop'];
// increment the $info['state'] element in $state_totals by $info['pop']
// to keep track of the total population of state $info['state']
$state_totals[$info['state']] += $info['pop'];
print "<tr><td>$city, {$info['state']}</td><td>{$info['pop']}</td></tr>\n";

}

// Iterate through the $state_totals array to print the per-state totals
foreach ($state_totals as $state => $pop) {
print "<tr><td>$state</td><td>$pop</td>\n";
}
print "<tr><td>Total</td><td>$total_population</td></tr>\n";
print "</table>\n";

?>

[chaking]

Try putting the following at the top:

$state_totals = array();

[BrentonHale]

Try putting the following at the top:

$state_totals = array();

 

Thank you, it took off the error Notice:  Undefined variable: state_totals in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

However, i'm still getting this:

 

Notice:  Undefined index: NY in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

Notice:  Undefined index: CA in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

Notice:  Undefined index: IL in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

Notice:  Undefined index: TX in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

Notice:  Undefined index: PA in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

Notice:  Undefined index: AZ in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

Notice:  Undefined index: MI in C:\wamp\www\chapter4_exercises_arrays.php on line 23

 

[dawsba]

works for me, you could try long calling the array name $population[$info]['state']

[ajaxmonk]

Branton:

The reason you are getting these errors is because you are trying to perform an + operation on a array key that does not exists yet. To get rid of the errors simply add the following line of code above line 26.

if(!isset($state_totals[$info['state']])) $state_totals[$info['state']]=0;

 

Dawsba:

To see the errors add the following lines of code at the top of the script

ini_set('display_errors', 1);
error_reporting(E_ALL);

 

Ajaxmonk

Clean, Custom PHP / Javascript

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