I work on the PHP framework Laravel 5, and here's my question :
I get from my DB an object with several values.
When I echo this, it show all the correct data, however, as soon as I cast it into an array, it becomes an empty array, why ?
$TonnageTotal = Collecte\Produit::pluck('tonnage'); //put everything I need into $TonnageTotal
$arrTonnage = get_object_vars($TonnageTotal); //then cast it
It does the same if I do this :
$arrTonnage=(array)$TonnageTotal;
Values I want to get are integer and are meant to be array_sum();
What am I missing ?
You may convert from collection to array by using toArray() method.
$arrTonnage = $TonnageTotal->toArray();
Related
I come from a Javascript and Ruby background and this is baffling me. Laravel can store two different array syntaxes in my DB depending on how I handle my array serialization. In my understanding, collect() creates a true Laravel array. Why then is it storing a serialized array? Furthermore, is the {'key':'value'}syntax still an array despite having no square brackets surrounding it? It looks to me like a standard object or a hash, but if I try to do toArray() on it, it recognizes that it's already an array and throws an error. What am I misunderstanding and what is correct here?
Given a form:
edit.blade:
<select class="form-control m-bootstrap-select m_selectpicker" name="temp">
<option value={{ json_encode(array("$key"=>"$cph"), JSON_FORCE_OBJECT) }}>
</select>
The following two controllers syntaxes yield different database insertions.
PageController.php:
$page->cph_default = collect($request->temp);
$page->save();
Laravel stores an array with the following syntax in my database: ["{\"11\":\"1100\"}"]
PageController.php
$page->cph_default = json_decode($request->temp, true);
$page->save();
Laravel stores an array with the following syntax in my database: {"19": "1900"}
A PHP array with the syntax ['key' => 'value'] is called an associative array, and acts like a hash. A JSON-encoded associative array will show up as an object in JSON syntax. Examples and more info on PHP.net
Laravel's collect() function is a convenience wrapper for creating a new Collection. A Collection is not really a "true Laravel array" so much as it is an object wrapper with some convenience methods for modifying the underlying array. Think of it like a scalar object.
In your form when generating the option value, the submitted form value ($request->temp) will be a JSON-encoded string. Literally the string '{"19": "1900"}'.
Calling collect($request->temp) does no modification to that submitted data. It's simply creating a new Collection (array), containing a single string item. If you were to call toArray() on the collection, you'd see something like this:
[
0 => '{"19": "1900"}'
]
Note that this is not an associative array, it is a numeric array with a zero-based index. This array is encoded as a JSON array, not as a hash object. Hence your first result.
Calling json_decode($request->temp) is turning the string back into an associative array (hash) before saving it via Eloquent. Eloquent then calls json_encode() again internally, turning it back into the same JSON as your form's option value.
If you were to decode the form value before creating the collection, the resulting database save would look identical. You'd just have the convenience of the Collection wrapper:
$page->cph_default = collect(json_decode($request->temp, true));
$page->save();
If you're treating the column as a JSON type, you should ensure the data passed to Eloquent is NOT already encoded, or you'll get the double encoding experienced in your first example.
No Matter What is.
First If you are stroring the array into database convert to JSON FORMAT
For eg
$variable = json_encode($request->controlname);
This is the right way to store array
Into database
I simply want to know how to access array elements retrieved from a database. I have the following code to get the names of each item in my database.
$plat_options = $this->db->get('tblplatform_options')->select('name')->result();
How do I go about accessing the name from the array $plat_options? Typically I would do $plat_options[0] for the first element in C#, how is this done in php/codeigniter?
In PHP/Codeigniter, can be done in the same way:
$plat_options[0] //if you have this element, usually is better to check if exists.
You can retrieve all the elements with foreach($plat_options as $option){...}
You can cast to object: https://www.kathirvel.com/php-convert-or-cast-array-to-object-object-to-array/
Or use a Codeigniter Helper (assuming you are using CI3): http://www.codeigniter.com/user_guide/helpers/array_helper.html
I recomend to know which is your array format and retrieve that way (if you don't know, you can do a: var_dump($plat_options) ) to know if is an associative array.
You can use the result_array() function:
$data = $plat_options->result_array();
echo($data[0]['name']);
or:
$data = array_shift($q->result_array());
echo($data['name']);
I extracted this last part from: Codeigniter $this->db->get(), how do I return values for a specific row? that you could check too.
If you don't know a lof of CI, the best you can do is do a simple tutorial to understand how the data + ActiveRecord works.
Hope it helps!
So im trying to figure out the best way to get MySql table data into either a multidimensional PHP array or convert that multidimensional array into a json string.
Essentially what im trying to do is have a php include that returns the JSON string so i can iterate through it. I am needing a single key with multiple values, so im not 100% sure that im headed in the right direction.
I want to assign multiple values to the same key, for example:
[{"key1": "package1", "package2", "package3"}, {"key2": "package1", "package2", "package3", "package4"}]
I think that is not going to work right? Because i dont have any type of index's?
That is not valid JSON. The structure you are looking for would be something like:
[
{"key1": ["package1", "package2", "package3"]},
{"key2": ["package1", "package2", "package3", "package4"}]
^ An array as the value to the key "key1", "key2", etc..
]
At the PHP side, you would need something like:
For every row fetched from MySQL
$arr[$key] = <new array>
for each package:
append package to $arr[$key]
echo out json_encode($arr)
JS arrays have an implicit array keying, starting at index 0. What you've got is a perfectly valid JS array, the equivalent of having written:
var x = []; // create new empty array
x[0] = {"key1": .... }; // first object
x[1] = {"key2": ....} // second object
Note that the contents of your {} sub-objects is NOT valid.
You should never EVER built a JSON string by hand. It's too unreliable and easy to mess up. It's just easier to use a native data structure (php arrays/objects), then json_encode() them. Ditto on the other end of the process - don't decode the string manually. Convert to a native data structure (e.g. json_decode(), JSON.parse()) and then deal with the native structure directly.
essentially, JSON is a transmission format, not a manipulation format.
I have a multidiminsional array that I have created in php that is passed back to a jQuery script. I need to iterate through this array and process the data.
In Firebug I can see that the data is located at data.data.items. I've tried finding the length of the array using data.data.items.length, but it comes back as undefined. Interestingly, this worked prior to my php portion working correctly when it passed back an array of 8 empty items. Now that it's populated (and the indexes are strings), length doesn't work. There is also an object in each of the items. What's breaking this?
An Array in JavaScript is an object nonetheless. When setting values using strings (or anything that isn't an integer), you are actually setting a property of the object (you are actually doing this when setting it with integer keys as well, but it's handled slightly differently).
To the issue of its sudden breakage after using strings as keys, I would expect that PHP realizes when you have an honest-to-goodness array versus an associative array, thus it sends arrays (surrounded by []) when all keys are integers, and objects (surrounded by {}) otherwise. I believe in the string-keyed case, PHP is generating objects, and thus .length becomes undefined (rather than 0 as in an empty array).
To answer your question, there is a simple way to count the "length" of this data:
var i = 0;
for (var item in data.data.items) {
i++;
}
Which will iterate through each property of data.data.items and count them. Note that if you (or any library you include) adds a property to the Object prototype, this will not produce expected results. This is fairly uncommon, but you must be aware of it when using for..in.
You can address this by using the method Nagh suggested, which ignores properties not defined on that particular object:
var i = 0;
for (var item in data.data.items) {
if(data.data.items.hasOwnProperty(item)) {
i++;
}
}
You can always use "foreach" kind of loop. In this case, you don't need to know what array length is there or even is it array or not, since you can iterate over object properties aswell.
As Joe already has pointed, javascript doesn't have associative arrays and when you trying to use one - you end up with object with properties. However, if u sure, that only properties this object got - is your array you can use code like that:
for (i in arr) {
if (arr.hasOwnProperty(i)) {
//do something with arr[i]
}
}
However if you really need an array, consider using integer as an array index.
i have an simple array:
array
0 => string 'Kum' (length=3)
1 => string 'Kumpel' (length=6)
when I encode the array using json_encode(), i get following:
["Kum","Kumpel"]
My question is, what is the reason to get ["Kum","Kumpel"] instead of { "0" : "Kum", "1" : "Kumpel" }?
"{}" brackets specify an object and "[]" are used for arrays according to JSON specification. Arrays don't have enumeration, if you look at it from memory allocation perspective. It's just data followed by more data, objects from other hand have properties with names and the data is assigned to the properties, therefore to encode such object you must also pass the correct property names. But for array you don't need to specify the indexes, because they always will be 0..n, where n is the length of the array - 1, the only thing that matters is the order of data.
$array = array("a","b","c");
json_encode($array); // ["a","b","c"]
json_encode($array, JSON_FORCE_OBJECT); // {"0":"a", "1":"b","2":"c"}
The reason why JSON_FORCE_OBJECT foces it to use "0,1,2" is because to assign data to obeject you must assign it to a property, since no property names are given by developer (only the data) the encoder uses array indexes as property names, because those are the only names which would make sense.
Note: according to PHP manual the options parameters are only available from PHP 5.3.
For older PHP versions refer to chelmertz's answer for a way to make json_encode to use indexes.
As Gumbo said, on the JS-side it won't matter. To force PHP into it, try this:
$a = new stdClass();
$a->{0} = "Kum";
$a->{1} = "Kumpel";
echo json_encode($a);
Not that usable, I'd stick with the array notation.
Just cast as an object and it will work fine...the JSON_FORCE_OBJECT parameter does exactly the same thing.
json_encode((object)$array);
Don't forget to convert it back into a php array so you can access its values in php:
$array = (object)$array;
$array = (array)$array;
json_encode($array);
Since you’re having a PHP array with just numeric keys, there is no need to use a JavaScript object. But if you need one, try Maiku Mori’s suggestion.
I personally think this is a bug that needs to be fixed in PHP. JSON_FORCE_OBJECT is absolutely not an answer. If you try to do any sort of generic programming you get tripped up constantly. For example, the following is valid PHP:
array("0" => array(0,1,2,3), "1" => array(4,5,6,7));
And should be converted to
{"0": [0,1,2,3], "1": [4,5,6,7]}
Yet PHP expects me to either accept
[[0,1,2,3],[4,5,6,7]]
or
{"0":{"0":1,"1":1,"2":2,"3":3},"1":{"0":4,"1":5,"2":6,"3":7}}
Neither of which are right at all. How can I possibly decode an object like that? What possible reason is there to ever change something that is clearly using strings as indexes? It's like PHP was trying to be clever to help out idiotic people who can't differentiate strings from ints, but in the process messed up anyone legitimately using strings as indexes, regardless of what the value COULD be turned into.