Basic associative arrays in php. How to fill them - php

Question

First of all, I'm sorry if this is too easy for many of you... I'm learning as much as I can.
I want to create an array with customers, like:
$customers=["customer A", "customer B", "customer C"];
Then, I want to create an array with some characteristics for every customer in that array. The characteristics are 'City', 'Points' and 'Results'. Each customer has a name (string), not a number.
I would need to change (or update) a characteristic ('points') of all customers of the array when needed with PHP. Something like:
for each $customer in $customers {
$points[$customer]=$points[$customer]+2;
}
I would like to also update the info of only one customer, something like:
$points['Customer C']=$points['Customer B']+3;
Finally, I need to access the characteristics of a give Customer, like:
$i=$points['Customer A']+$result['Customer A'];
I know this is not correct, but how should I proceed in PHP?
How could I eliminate a Customer from the array $Customers (with all its characteristics)? And how could I add a new Customer to $Customers?
Thank you very much for your help. I really appreciate it.

Answer 1

As your question states, assoc array:
$customers = [
'customerA' => [
'points' => 100,
'city' => 'New York',
'results' => 40,
],
'customerB' => [
'points' => 75,
'city' => 'Amsterdam',
'results' => 10,
],
'customerC' => [
'points' => 25,
'city' => 'London',
'results' => 5,
],
];
// Remove customer C
unset($customers['customerC']);
// add customer D
$customers['customerD'] = [
'points' => 50,
'city' => 'Berlin',
'results' => 5,
];
// Update points of customer
$customers['customerA']['points'] += 2; // Adds 2 points
// Update points of customer by another customers points
$customers['customerB']['points'] = $customers['customerA']['points'] + 3;
// Add 2 points to each customer
foreach ($customers as $name => $properties) {
$properties['points'] += 2;
$customers[$name] = $properties;
}
The key within the customers array is the name of your customer and all the properties are within the value of that key.

Answer 2

You were close with your foreach:
foreach ($customers as $customer) {
$points[$customer] = $points[$customer] + 2;
}
You can update a single value like this:
$points['customer A'] = $points['customer A'] + 2;
And you can unset/remove a value like this:
unset($points['customer A']);

Answer 3

$customers = array();
//Adding customers
$customers["Customer 1"]["City"] = "Houston";
$customers["Customer 1"]["points"] = 3;
$customers["Customer 1"]["Results"] = "";
$customers["Customer 2"]["City"] = "Paris";
$customers["Customer 2"]["points"] = 8;
$customers["Customer 2"]["Results"] = "";
//updating characteristics
foreach ($customers as $name=>$customer)
{
$customers[$name]["City"] = "Dallas";
$customers[$name]["points"] = $customers[$name]["points"] + 2;
$customers[$name]["Results"] = "";
}
//Removing customer
unset($customers["Customer 1"]);

Answer 4

You can use multidimensional arrays to hold the data. This will be like how data would be returned from a database request so is a good approach to use.
// Customers array
$customers = [
[
'name' => 'Customer A',
'city' => 'Townville',
'points' => '3',
'results' => '2',
],
[
'name' => 'Customer B',
'city' => 'Blagstonberry',
'points' => '1',
'results' => '4',
],
[
'name' => 'Customer C',
'city' => 'Thorpington',
'points' => '6',
'results' => '3',
],
];
To access or edit specific customer details you will need to get the key for that customer. For example, get the key for Customer A,
$key = array_search('Customer A', array_column($customers, 'name'));
Now to access that customer's city for example, you can use the code,
$customer_a_city = $customers[$key]['city'];
To remove Customer B,
// get the key
$key = array_search('Customer B', array_column($customers, 'name'));
// remove customer
unset($customers[$key]);
Add 2 points to all customers,
foreach ($customers as &$customer) {
$customer['points'] += 2;
}
unset($customer);
Here we are passing by reference using the &. This means we can update the value directly in the foreach loop. It is good practice to unset the variable, in this case $customer so that you don't make any unwanted changes later on.
Characteristics of a particular customer - Customer C,
// get the key
$key = array_search('Customer C', array_column($customers, 'name'));
$i = $customers[$key]['points'] + $customers[$key]['results'];
Add a customer,
$customers[] = [
'name' => 'Customer D',
'city' => 'Dongleville',
'points' => '7',
'results' => '1',
];
Notes
If you search for a key for a customer by name that doesn't exist $key will be false. For example,
// get the key
$key = array_search('MADE UP NAME', array_column($customers, 'name'));
if ($key === false) {
// customer name did not exist
} else {
// do your thing
}
Also if more than one customer has the same name, the first customer key will be returned.
Reference
Passing by reference
Array search
Array column