i have this array
$array = [1, 2, 3, 4, 5];
and this function
function change($array) {
foreach ($array as $key => $value) {
$form[$key+5][$value-1] = $key-$value;
}
return $form;
}
change($array);
in it the form that i want to rearrange the array in is $form[$key+5][$value-1] = $key-$value; but i want to make it defined by a parameter like this
function change($array, $form) {
foreach ($array as $key => $value) {
$form;
}
return $form;
}
$x = change($array, $arr[$key+5][$value-1] = $key-$value);
$y = change($array, $arr[$key+5][$key+100] = $key+$value);
how can this be done?
Somebody will bash all of the evils of eval but if it is not user supplied (un-trusted) data, then this works:
function change($array, $form) {
foreach ($array as $key => $value) {
eval("\$result$form;");
}
return $result;
}
You need to call it with a string as shown:
$x = change($array, '[$key+5][$value-1] = $key-$value');
$y = change($array, '[$key+5][$key+100] = $key+$value');
This builds a string that looks like this: $result[$key+5][$key+100] = $key+$value; and evaluates it as PHP code.
It would be a lot more work, but you could pass in something to parse and adapt it to How to access and manipulate multi-dimensional array by key names / path?.
Related
Given I have an simple non-associative array $values of SomeObject items indexed by 0, 1, 2, etc.
What is the best syntax to construct associative array $valuesByIndex indexed by some value extracted from original items?
What I constructed is:
$key = function($val) {
return $val->getSomeProperty();
};
$valuesByIndex = array_combine(array_map($key, $values), $values);
Which is pretty equals to:
$key = function($val) {
return $val->getSomeProperty();
};
$valuesByIndex = [];
foreach ($values as $val) {
$valuesByIndex[$key($val)] = $val;
}
Looking for pretty compact syntax.
In this piece:
$key = function($val) {
return $val->getSomeProperty();
};
$valuesByIndex = [];
foreach ($values as $val) {
$valuesByIndex[$key($val)] = $val;
}
We can simply replace $key($val) with the contents of the function $val->getSomeProperty() Which gives us
$valuesByIndex = [];
foreach ($values as $val) $valuesByIndex[$val->getSomeProperty()] = $val;
Because if the function returns this $val->getSomeProperty() we can just put it right in there and forgo that function completely.
However if this is from a DB call you may be able to use (in PDO) PDO::FETCH_GROUP which takes the first column of the Select and makes it the top level key.
I got an array like this:
$array[0][name] = "Axel";
$array[0][car] = "Pratzner";
$array[0][color] = "black";
$array[1][name] = "John";
$array[1][car] = "BMW";
$array[1][color] = "black";
$array[2][name] = "Peggy";
$array[2][car] = "VW";
$array[2][color] = "white";
I would like to do something like "get all names WHERE car = bmw AND color = white"
Could anyone give advice on how the PHP spell would look like?
function getWhiteBMWs($array) {
$result = array();
foreach ($array as $entry) {
if ($entry['car'] == 'bmw' && $entry['color'] == 'white')
$result[] = $entry;
}
return $result;
}
Edited: This is a more general solution:
// Filter an array using the given filter array
function multiFilter($array, $filters) {
$result = $array;
// Removes entries that don't pass the filter
$fn = function($entry, $index, $filter) {
$key = $filter['key'];
$value = $filter['value'];
$result = &$filter['array'];
if ($entry[$key] != $value)
unset($result[$index]);
};
foreach ($filters as $key => $value) {
// Pack the filter data to be passed into array_walk
$filter = array('key' => $key, 'value' => $value, 'array' => &$result);
// For every entry, run the function $fn and pass in the filter data
array_walk($result, $fn, $filter);
}
return array_values($result);
}
// Build a filter array - an entry passes this filter if every
// key in this array corresponds to the same value in the entry.
$filter = array('car' => 'BMW', 'color' => 'white');
// multiFilter searches $array, returning a result array that contains
// only the entries that pass the filter. In this case, only entries
// where $entry['car'] = 'BMW' AND $entry['color'] = 'white' will be
// returned.
$whiteBMWs = multiFilter($array, $filter);
Doing this in code is more or less emulating what a RDBMS is perfect for. Something like this would work:
function getNamesByCarAndColor($array,$color,$car) {
$matches = array();
foreach ($array as $entry) {
if($entry["color"]== $color && $entry["car"]==$car)
matches[] = $entry["name"];
}
return $matches;
}
This code would work well for smaller arrays, but as they got larger and larger it would be obvious that this isn't a great solution and an indexed solution would be much cleaner.
I found a way to search my multidimensional array and output the result and it works, however it only finds the first match and stops. If I have more than one match in the array I want to be able to show them all.
My array looks like this (the first layer of keys goes from 0, 1, 2 etc):
Array
(
[0] => Array
(
[mydevice] => blahblah
[ipadd] => 10.10.10.209
[portnum] => 16040
)
function searcharray($value, $key, $array) {
foreach ($array as $k => $val) {
if ($val[$key] == $value) {
return $k;
}
}
return null;
}
$myoutput = searcharray($ptn2, mydevice, $newresult);
I can then echo the results using something like $newresult[$myoutput][mydevice].
However if I have more than one entry in the array with a matching data in the 'mydevice' key it doesn't return them (just the first one).
That is because return breaks the function. You could use something like this:
function searcharray($value, $key, $array) {
$result = array();
foreach ($array as $k => $val) {
if ($val[$key] == $value) {
$result[] = $k;
}
}
return $result;
}
Now you will always get an array as result - empty if nothing was found. You can work with this like this e.g.
$mydevicekeys = searcharray($ptn2, "mydevice", $newresult);
foreach ($mydevicekeys as $mydevicekey) {
// work with $newresult[ $mydevicekey ]["mydevice"]
}
So add the results to an array :)
function searcharray($value, $key, $array) {
$res = array();
foreach ($array as $k => $val) {
if ($val[$key] == $value) {
$res[] = $key;
}
}
return $res;
}
I am trying to make first array value to uppercase.
Code:
$data = $this->positions_model->array_from_post(array('position', 'label'));
$this->positions_model->save($data, $id);
So before save($data, $id) to database I want to convert position value to uppercase. I have tried by this
$data['position'] = strtoupper($data['position']);
but than it is not storing the value in db with uppercase but as it is what user inputs.
Current output of $data:
Array ( [position] => it [label] => Information Technology )
And I want it in uppercase as IT
Added Model Method
public function get_positions_array($id = NULL, $single = FALSE)
{
$this->db->get($this->_table_name);
$positions = parent::get($id, $single);
$array = array();
foreach($positions as $pos){
$array[] = get_object_vars($pos);
}
return $array;
}
Main MY_Model method
public function array_from_post($fields)
{
$data = array();
foreach ($fields as $field) {
$data[$field] = $this->input->post($field);
}
return $data;
}
This should work:
$data = $this->positions_model->array_from_post(array('position', 'label'));
$data['position'] = strtoupper($data['position']);
$this->positions_model->save($data, $id);
If Its not, then $data array have only read attribute.
The array_from_post() method returns an array with the format below:
$data = array(
'position' => 'it',
'label' => 'Information Technology'
);
So, you could make first value of the array to uppercase, by using array_map or array_walk functions as follows:
$data = array_map(function($a) {
static $i = 0;
if ($i === 0) { $i++; return strtoupper($a); }
else return $a;
}, $array);
Note: This only works on PHP 5.3+, for previous versions, use the function name instead.
Here is the array_walk example, which modifies the $data:
array_walk($data, function(&$value, $key) {
static $i = 0;
if ($i == 0) { $i++; $value = strtoupper($value); }
});
Again, if you're using PHP 5.2.x or lower, you could pass the function name instead.
I would like to split an array:
$o = json_decode('[{"id":"1","color":"green"},{"id":"2","color":"green"},{"id":"3","color":"yellow"},{"id":"4","color":"green"}]');
based on the color attribute of each item, and fill corresponding sub arrays
$a = array("green", "yellow", "blue");
function isGreen($var){
return($var->color == "green");
}
$greens = array_filter($o, "isGreen");
$yellows = array_filter($o, "isYellow");
// and all possible categories in $a..
my $a has a length > 20, and could increase more, so I need a general way instead of writing functions by hand
There doesn't seem to exist a function array_split to generate all filtered arrays
or else I need a sort of lambda function maybe
You could do something like:
$o = json_decode('[{"id":"1","color":"green"},{"id":"2","color":"green"},{"id":"3","color":"yellow"},{"id":"4","color":"green"}]');
$greens = array_filter($o, function($item) {
if ($item->color == 'green') {
return true;
}
return false;
});
Or if you want to create something really generic you could do something like the following:
function filterArray($array, $type, $value)
{
$result = array();
foreach($array as $item) {
if ($item->{$type} == $value) {
$result[] = $item;
}
}
return $result;
}
$o = json_decode('[{"id":"1","color":"green"},{"id":"2","color":"green"},{"id":"3","color":"yellow"},{"id":"4","color":"green"}]');
$greens = filterArray($o, 'color', 'green');
$yellows = filterArray($o, 'color', 'yellow');
In my second example you could just pass the array and tell the function what to filter (e.g. color or some other future property) on based on what value.
Note that I have not done any error checking whether properties really exist
I would not go down the road of creating a ton of functions, manually or dynamically.
Here's my idea, and the design could be modified so filters are chainable:
<?php
class ItemsFilter
{
protected $items = array();
public function __construct($items) {
$this->items = $items;
}
public function byColor($color)
{
$items = array();
foreach ($this->items as $item) {
// I don't like this: I would prefer each item was an object and had getColor()
if (empty($item->color) || $item->color != $color)
continue;
$items[] = $item;
}
return $items;
}
}
$items = json_decode('[{"id":"1","color":"green"},{"id":"2","color":"green"},{"id":"3","color":"yellow"},{"id":"4","color":"green"}]');
$filter = new ItemsFilter($items);
$greens = $filter->byColor('green');
echo '<pre>';
print_r($greens);
echo '</pre>';
If you need more arguments you could use this function:
function splitArray($array, $params) {
$result = array();
foreach ($array as $item) {
$status = true;
foreach ($params as $key => $value) {
if ($item[$key] != $value) {
$status = false;
continue;
}
}
if ($status == true) {
$result[] = $item;
}
}
return $result;
}
$greensAndID1 = splitArray($o, array('color' => 'green', 'id' => 1));