What is better and fast:
$objectTypes = array(
1=>'Content',2=>'Taxonomy',3=>'Ad',4=>'Issue'
);
ID: $objectTypes[1];
Title: array_search('Content',$objectTypes);
VS
$objectTypes = array(
1=>'Content',2=>'Taxonomy',3=>'Ad',4=>'Issue',
'Content'=>1,'Taxonomy'=>2,'Ad'=>3,'Issue'=>4);
ID: $objectTypes[1];
Title: $objectTypes['Content'];
IN first I use array_search to get the id of object.
In second I just store it other way round.
Mostly the object is not going to change and it won't have more than 5-10 types
I need to store the object id and title
I am just curious for use of the method vs large array
ofcourse when i use it in class, i'll use proper function to get/set
Performance is first preference, but a good coding style and optimum use of class objects/files is also important.
The second one is not recommended. There is no point in saving the same data twice and think about all the wasted time populating the unnecessary data. So to answer your question array_search will do you better
Related
This is probably considered a really silly question, but I'm in the process of putting together a simple template system for a website and am trying to keep track of my variable usage and keep everything neat and tidy.
Can you tell me if there is any advantage/disadvantage to the following methods:
simple var:
$tpl_title = 'my title'
$tpl_desc = 'my text'
array:
$tpl['title'] = 'my title'
$tpl['desc'] = 'my text'
Object:
$tpl->title = 'my title'
$tpl->desc = 'my text'
I like the object method the best as it looks clean when echo'd within html as opposed to arrays and afaik it can be used in an array-like way? However, what I want to know is whether using objects in this way is considered bad practice or introduces unneccesary overheads?
In ideal scenarios every variable should belong to an object, other than the variables local to methods for temp purposes. However we don't live in an ideal world and specially our programming languages are far from it. Based on what the situation is, choose the best way to go about it to make your life easier. If you are using things for templates, generally you keep all the data in an array and extract the array to get stand alone variables.
So yeah, the object method is the nicest, try to make it happen as much as you can without spending crazy amounts of time in doing it.
Also if you love objects and want to have the neat -> way of doing it, you can do
$object = (object)$array;
That would convert your array to an object.
Hope that helps.
I would consider it unnecessary overhead. Doing what you are talking about in an object-oriented way only means that inside your class you will have done nothing more than create a bunch of variables, just as you specified in your first example.
The array is the best way to go in my opinion. You are only using one variable, and you can also integrate it into your Class. So, instead of $tpl->title, you may have $tpl->text['title'].
Arrays
I would suggest on the backend part, keep everything stored in an array. This allows you to have only one variable to keep track of, and once you pass it to the frontend, you can extract() the array, to convert them into simple variables.
Syntax
Using extract() simplifies the syntax on the FrontEnd, which means you will only always have $varibles in the template.
On the backend you would set
$array['title'];
Which once extracted would in the template be
$title;
Example of a backend function
protected function fetch($template, $data = null)
{
if (!$this->isTemplate($template)) {
throw new Exception("Template file $this->_templatePath$template not found");
}
ob_start();
if (is_array($data)) {
extract($data, EXTR_SKIP);
}
require $this->_templatePath . $template . EXT;
return ob_get_clean();
}
In the end they are the same, It depends on the preference, although I would use arrays or objects because you can group variables in there, so you have things better sorted out.
Despite the objects method works I think it's not the natural intended use for it.
So I would say arrays!
Also, there are tons of php native functions you can use with arrays, like array_map() or array_filter() array sortings and etc etc...
In my opinion the cleanest way to set it up is in array like this:
$tpl = array (
'title' => 'my title',
'desc' => 'my text'
);
You can combine it with Zane's answer also.
All the best!
$tpl = array (
'title' => 'my title',
'desc' => 'my text'
);
Like Goran said, with the bonus that you could store these arrays in an ini file later and extract them as needed with parse_ini_file
Could be important if you want to permit users to write to their own ini file.
arrays and objects are useful in case if you want to reset bulk of variable data after use it.
you can simply unset the array or destroy the object instead of unset range of variables use in a code.
Other than this arrays and objects have more symmetry in code and explanatory than normal variables
What would you say is the most efficient way to get a single value out of an Array. I know what it is, I know where it is. Currently I'm doing it with:
$array = unserialize($storedArray);
$var = $array['keyOne'];
Wondering if there is a better way.
You are doing it fine, I can't think of a better way than what you are doing.
You unserialize
You get an array
You get value by specifying index
That's the way it can be done.
Wondering if there is a better way.
For the example you give with the array, I think you're fine.
If the serialized string contains data and objects you don't want to unserialize (e.g. creating objects you really don't want to have), you can use the Serialized PHP library which is a complete parser for serialized data.
It offers low-level access to serialized data statically, so you can only extract a subset of data and/or manipulate the serialized data w/o unserializing it. However that looks too much for your example as you only have an array and you don't need to filter/differ too much I guess.
Its most efficient way you can do, unserialize and get data, if you need optimize dont store all variables serialized.
Also there is always way to parse it with regexp :)
If you dont want to unseralize the whole thing (which can be costly, especially for more complex objects), you can just do a strpos and look for the features you want and extract them
Sure.
If you need a better way - DO NOT USE serialized arrays.
Serialization is just a transport format, of VERY limited use.
If you need some optimized variant - there are hundreds of them.
For example, you can pass some single scalar variable instead of whole array. And access it immediately
I, too, think the right way is to un-serialize.
But another way could be to use string operations, when you know what you want from the array:
$storedArray = 'a:2:{s:4:"test";s:2:"ja";s:6:"keyOne";i:5;}';
# another: a:2:{s:4:"test";s:2:"ja";s:6:"keyOne";s:3:"sdf";}
$split = explode('keyOne', $storedArray, 2);
# $split[1] contains the value and junk before and after the value
$splitagain = explode(';', $split[1], 3);
# $splitagain[1] should be the value with type information
$value = array_pop(explode(':', $splitagain[1], 3));
# $value contains the value
Now, someone up for a benchmark? ;)
Another way might be RegEx ?
I need to create an association between an Array and a Number; as PHP lacks a Map type, I am trying using an array to achieve this:
$rowNumberbyRow = array();
$rowNumberByRow[$rowData] = $rowNumber;
However, when I evaluate the code, I get the following Error:
Warning: Illegal offset type
Just to note, the data stored in the array ($rowData) does not have any 'unique' values that I can use as a key for the $rowNumberByRow Array.
Thanks!
UPDATE:
To answer some of my commenters, I am trying to create a lookup table so that my application can find the row number for a given row in O(1) time.
PHP does have a map Class: It's called SplObjectStorage. It can be accessed with exactly the same syntax as a general array is (see Example #2 on the reference).
But to use the class you will have to use the ArrayObject class instead of arrays. It is handled exactly the same way arrays are and you can construct instances from arrays (e.g. $arrayObject = new ArrayObject($array)).
If you don't want to use those classes, you can also just create a function that creates unique hash-strings for your indexes. For example:
function myHash($array){
return implode('|',$array);
}
$rowNumberByRow[myHash($array)] = $rowNumber;
You will of course have to make sure that your hashes are indeed unique, and I would strongly suggest you use the SplObjectStorage and maybe read a little bit more about the SPL classes of php.
Why not just store the row number in the array? e.g:
$rowData['rowNumber'] = $rowNumber;
You could instead serialize the array, e.g:
$rowNumberByRow[serialize($rowData)] = $rowNumber;
However that's pretty inefficient.
In php you can use only scalar values as an array keys.
If your $rowNumber is unique - then you'd try to use the opposite relation direction. If it is not unique - then you don't have any possible solution I know.
The answer has been alredy given and accepted, but while i was searching for a similar problem, i found this question, and i felt like i should drop a line: when someone wants to use an array with values as keys for another array, it would be useful to use the function array_combine.
If i got the arrays correctly, you could use:
$rowNumberByRow = array_combine($rowData, $rowNumber);
Please take a look at the PHP manual to see some info about permitted values for the keys :)
I am new to php. I was wondering how I could declare a static array in php. Here is what I would do in C. How is the corresponding php code for it?
char a[][] = { (1,1), (1,2), (1,3), (2,1), (2,2), (2,3), (3,1), (3,2), (3,3) };
From what I read it has to be something like this -
$a = array( 1 => array(1,1), 2 => array(1,2), ... );
Is this correct? If so it sucks :) I hope I am wrong.
Thanks,
- Pav
You've already found the way to do it natively.
Another option would be to declare your data as JSON (a very concise and human-friendly format). This could be either in a separate file bundled with your app, or directly in your code in a string. Then parse the JSON at runtime. Since PHP isn't exactly known for speed, this may or may not make your noticeably app slower to start.
you have it already figured out in your question.
One thing I would add is that you do not need to explicitly define the keys if you are intending to use a zero based array, this is assumed and can be done like so...
$a = array(array(1,1),array(1,2), ... );
You can also use what is called associative arrays which use string keys and you define them the same way you do in your example, except use strings instead of numbers...
$ass_array = array( 'array_1' => array(1,1), 'array_2' => array(1,2), ... );
you would then call your associative array like this...
$ass_array['array_1'];
Also, if you want to append single items to an array (for example in a loop to load an array)...
$ass_array[] = $item;
Further to jondavidjohn's anwser, you could just write a quick script to grab your list of values and generate the array statement for you.
No need to care how verbose the syntax is then. If the task is long and repetitious enough to care, don't do it by hand. :)
The reason I am asking this question is because I have landed my first real (yes, a paid office job - no more volunteering!) Web Development job about two months ago. I have a couple of associates in computer information systems (web development and programming). But as many of you know, what you learn in college and what you need in the job site can be very different and much more. I am definitely learning from my job - I recreated the entire framework we use from scratch in a MVC architecture - first time doing anything related to design patterns.
I was wondering what you would recommend as the best way to pass/return values around in OO PHP? Right now I have not implement any sort of standard, but I would like to create one before the size of the framework increases any more. I return arrays when more than 1 value needs to get return, and sometimes pass arrays or have multiple parameters. Is arrays the best way or is there a more efficient method, such as json? I like the idea of arrays in that to pass more values or less, you just need to change the array and not the function definition itself.
Thank you all, just trying to become a better developer.
EDIT: I'm sorry all, I thought I had accepted an answer for this question. My bad, very, very bad.
How often do you run across a situation where you actually need multiple return values? I can't imagine it's that often.
And I don't mean a scenario where you are returning something that's expected to be an enumerable data collection of some sort (i.e., a query result), but where the returned array has no other meaning that to just hold two-or-more values.
One technique the PHP library itself uses is reference parameter, such as with preg_match(). The function itself returns a single value, a boolean, but optionally uses the supplied 3rd parameter to store the matched data. This is, in essence, a "second return value".
Definitely don't use a data interchange format like JSON. the purpose of these formats is to move data between disparate systems in an expected, parse-able way. In a single PHP execution you don't need that.
You can return anything you want: a single value, an array or a reference (depending on the function needs). Just be consistent.
But please don't use JSON internally. It just produces unnecessary overhead.
I also use arrays for returning multiple values, but in practice it doesn't happen very often. If it does, it's generally a sensible grouping of data, such as returning array('x'=>10,'y'=>10) from a function called getCoordinates(). If you find yourself doing lots of processing and returning wads of data in arrays from a lot of functions, there's probably some refactoring that can be done to put the work into smaller units.
That being said, you mentioned:
I like the idea of arrays in that to pass more values or less, you just need to change the array and not the function definition itself.
In that regard, another technique you might be interested in is using functions with variable numbers of arguments. It is perfectly acceptable to declare a function with no parameters:
function stuff() {
//do some stuff
}
but call it with all the parameters you care to give it:
$x = stuff($var1, $var2, $var3, $var4);
By using func_get_args(), func_get_arg() (singular) and func_num_args() you can easily find/loop all the parameters that were passed. This works very well if you don't have specific parameters in mind, say for instance a sum() function:
function sum()
{
$out = 0;
for($i = 0; $i < $c = func_num_args(); $i++) {
$out += func_get_arg($i);
}
return $out;
}
//echoes 35
echo sum(10,10,15);
Food for thought, maybe you'll find it useful.
The only thing I'm careful to avoid passing/returning arrays where the keys have "special" meaning. Example:
<?php
// Bad. Don't pass around arrays with 'special' keys
$personArray = array("eyeColor"=>"blue", "height"=>198, "weight"=>103, ...);
?>
Code that uses an array like this is harder to refactor and debug. This type of structure is better represented as an object.
<?php
Interface Person {
/**
* #return string Color Name
*/
public function getEyeColor();
...
}
?>
This interface provides a contract that the consuming code can rely on.
Other than that I can't think of any reason to limit yourself.
Note: to be clear, associative arrays are great for list data. like:
<?php
// Good array
$usStates = array("AL"=>"ALABAMA", "AK"="ALASKA", ... );
?>