how to add elements to an array in a loop using php

Question

I am dynamically trying to populate a multidimensional array and having some trouble.

I have a list of US states. Associative array like this $states[nc], $states[sc], etc. in my loop I want to append cities onto each state so $states[nc][cities] contains an array of cities. Im stuck with the logic.

foreach($states as $state) {
    $data[$state] = $state;

    foreach($cities as $city) {
      $data[$state]['cities'] .= $city;
     }
}

I know that concatenation is not correct, but I am not sure how to add elements to this array. I keep getting errors with array_push.

What's the correct way to add these elements?

replacing the inner foreach with just $data[$state]['cities'] = $cities; should do the trick. — mwhite
– mwhite, Commented Mar 6, 2012 at 10:43

Jon · Accepted Answer · 2012-03-06 10:42:01Z

20

The same way you add to an array when the key is not a concern:

$data[$state]['cities'][] = $city;

answered Mar 6, 2012 at 10:42

Jon

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3 Comments

user658182 Over a year ago

that did it! I was trying to overcomplicate it, but that gives me the correct result. Thanks!

Jon Over a year ago

@user9437856 yes, it's one line of code, it's not difficult to execute it and see.

user9437856 Over a year ago

@Jon, Thanks for the reply. I was trying to implement your issue here : stackoverflow.com/questions/61977036/…

ckonig · Accepted Answer · 2012-03-06 10:44:19Z

17

In PHP, you can fill an array without referring to the actual index.

$newArray = array();
foreach($var in $oldArray){
$newArray[] = $var;
}

answered Mar 6, 2012 at 10:44

ckonig

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2 Comments

DarkSide Over a year ago

Much simpler syntax: $newArray = array_values($oldArray);

mickmackusa Over a year ago

foreach() with in? Nope. 3v4l.org/0vmXZ

PiTheNumber · Accepted Answer · 2012-03-06 10:44:11Z

4

To add an element, use empty brackets.

foreach($states as $state) {
    foreach($cities as $city) {
       $data[$state][] = $city;
    }
}

This will create an array like this

array(
  'nc' => array('city1', 'city2', ...),
  'sc' => array('city1', 'city2', ...)
)

See manual under "Creating/modifying with square bracket syntax"

answered Mar 6, 2012 at 10:44

PiTheNumber

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Comments

Harti · Accepted Answer · 2012-03-06 10:43:20Z

2

foreach($states as $state) {
    $data[$state] = $state;

    foreach($state->cities as $city) {
      $data[$state][] = $city;
    }
}

Using empty brackets adds an element to the array.

answered Mar 6, 2012 at 10:43

Harti

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