How PHP uses Http_build_query () to construct a URL string _php tips

This example describes how PHP uses Http_build_query () to construct a URL string. Share to everyone for your reference, specific as follows:

In short, http_build_query () is the conversion of an array to a URL question mark? The argument string that follows, and is automatically urlencode processed.

Or quote an official explanation:

Http_build_query

Http_build_query--Request string description after generation url-encoded string http_build_query (array formdata [, String Numeric_prefix])

Generates a url-encoded request string using the given associated (or subscript) array. Parameter formdata can be an array or an object that contains attributes. A formdata array can be either a simple one-dimensional structure or an array of arrays (which in turn can contain other arrays). If a numeric subscript is used in the underlying array and the Numeric_prefix parameter is given, this parameter value is prefixed to the numeric subscript element in the underlying array. This is to allow PHP or other CGI programs to obtain a valid variable name when decoding the data later.

Let's take a look at some simple examples:

$data = Array (
    ' foo ' => ' bar ', '
    baz ' => ' boom ',
    ' site ' => ' www.nowamagic.net ',
    ' name ' => ') Nowa Magic ');
echo Http_build_query ($data);
/* Output
 foo=bar&baz=boom&cow=milk&php=hypertext+processor
* *

What if it's an array of indexed arrays mixed with associative arrays?

$data = Array (
    ' foo ',
    ' bar ', '
    site ' => ' www.nowamagic.net ', '
    name ' => ' Nowa Magic ');
echo Http_build_query ($data);
/* Output
    0=foo&1=bar&site=www.nowamagic.net&name=nowa+magic
* *

It automatically adds a numeric index.

Http_build_query also has a parameter that can prefix the numeric index, let's try again:

$data = Array (
    ' foo ',
    ' bar ', '
    site ' => ' www.nowamagic.net ', '
    name ' => ' Nowa Magic ');
Echo http_build_query ($data, "nm_");
/* Output
nm_0=foo&nm_1=bar&site=www.nowamagic.net&name=nowa+magic
* *

What about the more complex arrays? Like a two-dimensional array or something.

$data = Array ('
    user ' =>array (' name ' => ' Bob Smith ',
    ' age ' =>47,
    ' sex ' => ' M ',
    ' dob ' => ' 5 /12/1956 '),
    ' pastimes ' =>array (' Golf ', ' opera ', ' Poker ', ' rap '),
    ' Children ' =>array (' Bobby ' =>array (' Age ' =>12, ' sex ' => ' M '),
    ' Sally ' =>array (' age ' =>8, ' sex ' => ' F ')),
    ' CEO ';

Its output results are:

user%5bname%5d=bob+smith&user%5bage%5d=47&user%5bsex%5d=m&user%5bdob%5d=5%2f12%2f1956
& Pastimes%5b0%5d=golf&pastimes%5b1%5d=opera&pastimes%5b2%5d=poker
&pastimes%5B3%5D=rap& Children%5bbobby%5d%5bage%5d=12&children%5bbobby%5d%5bsex%5d=m
&children%5bsally%5d%5bage%5d=8 &children%5bsally%5d%5bsex%5d=f&0=ceo

The line is folded for readability:

user[name]=bob+smith&user[age]=47&user[sex]=m&user[dob]=5%1f12%1f1956&
Pastimes[0]=golf &pastimes[1]=opera&pastimes[2]=poker&pastimes[3]=rap&
Children[bobby][age]=12&children [Bobby] [sex]=m&children[sally][age]=8&
Children[sally][sex]=f&flags_0=ceo

Note: Only the digital subscript element "CEO" in the underlying array gets the prefix, and other numeric subscript elements (such as elements under pastimes) do not need to prefix the valid variable names.

Not just an array, but even an object can be converted to a URL string:

Class MyClass {
  var $foo;
  var $baz;
  function MyClass () {
  $this->foo = ' bar ';
  $this->baz = ' boom ';
  }
}
$data = new MyClass ();
echo Http_build_query ($data);

At the end, a few more functions are probably what you need to know when you search for http_build_query:

1. Parse_str: Converts a URL back to an array of parameters, array parse_str (Url,arr).

2. Parse_url: Resolves a full URL to an array parse_url (string url).

3. Http_build_query: Again, briefly explain, convert an array to a URL? The argument string that follows is UrlEncode processed automatically, string http_build_query (array formdata [, String Numeric_prefix]), followed by a subscript that does not specify a key in the array or the key is a number.

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I hope this article will help you with the PHP program design.