Convert a string into an associative array key? - php

Question

Given a string that contains values separated by dots:
property.entry.item
What is the best way to convert that to a key for an associative array?
$result['imported_data']['property']['entry']['item']
The string may be of any length, with any number of dots and contain an value:
people.arizona.phoenix.smith
I've tried the following without success:
//found a dot, means we are expecting output from a previous function
if( preg_match('[.]',$value)) {
//check for previous function output
if(!is_null($result['import'])) {
$chained_result_array = explode('.',$value);
//make sure we have an array to work with
if(is_array($chained_result_array)) {
$array_key = '';
foreach($chained_result_array as $key) {
$array_key .= '[\''.$key.'\']';
}
}
die(print_r(${result.'[\'import\']'.$array_key}));
}
}
I was thinking I could convert the string to a variable variable, but I get an array to string conversion error.

Answer 1

You can explode the string into an array and loop through the array. (DEMO)
/**
* This is a test array
*/
$testArray['property']['entry']['item'] = 'Hello World';
/**
* This is the path
*/
$string = 'property.entry.item';
/**
* This is the function
*/
$array = explode('.', $string);
foreach($array as $i){
if(!isset($tmp)){
$tmp = &$testArray[$i];
} else {
$tmp = $tmp[$i];
}
}
var_dump( $tmp ); // output = Hello World

Answer 2

Split the string into parts, and itterate the array, accessing each element in turn:
function arrayDotNotation($array, $dotString){
foreach(explode('.', $dotString) as $section){
$array = $array[$section];
}
return $array;
}
$array = ['one'=>['two'=>['three'=>'hello']]];
$string = 'one.two.three';
echo arrayDotNotation($array, $string); //outputs hello
Live example: http://codepad.viper-7.com/Vu8Hhy

Answer 3

You should really check to see if keys exist before you reference them. Otherwise, you're going to spew a lot of warnings.
function getProp($array, $propname) {
foreach(explode('.', $propname) as $node) {
if(isset($array[$node]))
$array = &$array[$node];
else
return null;
}
return $array;
}
Now you can do things like:
$x = array(
'name' => array(
'first' => 'Joe',
'last' => 'Bloe',
),
'age' => 27,
'employer' => array(
'current' => array(
'name' => 'Some Company',
)
)
);
assert(getProp($x, 'age') == 27);
assert(getProp($x, 'name.first') == 'Joe');
assert(getProp($x, 'employer.current.name') == 'Some Company');
assert(getProp($x, 'badthing') === NULL);
assert(getProp($x, 'address.zip') === NULL);
Or, if you are only interested in the import section of the tree:
getProp($x['import'], 'some.path');