<A Basic PHP String.Format ⁄ >

15997

2008-06-25

mySnippets php

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Here's another one that I use a lot in .NET, String.Format.

Basically String.Format replaces an item with this format {x} (where X's an int) by its correspondent argument, you can do much more, such as format the item, for example format currency, decimal, dates, etc, etc.

Although this is a PHP snippet, you can get much more valid information in this link and take a glimpse at this method.

Well, unfortunately my String::Format won't be that complex, it will just replace items by its correspondent arguments.

I'll use 2 methods to reach this:
- regex patterns with str_replace;
- and other method only using str_replace;

In the method that uses Regex, preg_match_all will be the function used

Searches subject for all matches to the regular expression given in pattern and puts them in matches in the order specified by flags .
After the first match is found, the subsequent searches are continued on from end of the last match.

in php manual

In this line:

preg_match_all('/\{(\d+)\}/',self::$_str, $indexes,PREG_SET_ORDER);

All the pattern matches will be saved in an array named $indexes, here's a example:

Array(
    [0] => Array(
            [0] => {5}
            [1] => 5
           )

    [1] => Array(
            [0] => {6}
            [1] => 6
           )

    [2] => Array (
            [0] => {0}
            [1] => 0
           )
)

For example let's see this case:

[0] =>
  Array(
    [0] => {5}
    [1] => 5
  )

The first element in the sub-array tells us what item we'll replace and the second element tells us by what specific argument, confuse? Welcome aboard! ;)

class.String.php

<?php
/**
 * Class String
 *
 * This static class tries to implement String.Format
 * by using 2 methods. Both returns the same, however
 * one was made using Regex Patterns
 * 
 * @author pedrocorreia.net
 */
class String{
 
  private static $_str;
 
  /**
   * Format String using Regex Patterns
   *
   * @param String
   * @return String
   */
  public static function Format($str){
 
    self::$_str=$str;
 
    //count arguments that our function received
    $count_args=func_num_args();
    //check if we have sufficient arguments
    if($count_args==1){return $str;}
 
    //find all ocurrences that matches the pattern {(numbers)}
    //and copy them to an auxiliary array named $indexes
    //we'll use PREG_SET_ORDER so that we can get a pair of values
    //with all the matches found,
    //for example: array[y]=array([0]=>"{x}", [1]=>"x");
    preg_match_all('/\{(\d+)\}/',self::$_str, $indexes,PREG_SET_ORDER);
 
    $count=sizeof($indexes);
 
    //looping through our $indexes will give us
    //the elements to replace with
    for($i=0;$i<$count;$i++){
      $arr=$indexes[$i];
 
      //what will we replace, for example {x} (on which x=([0-9]+)
      $replace=$arr[0];
      //get argument value that will replace our {x}
      $arg_pos=$arr[1]+1;
 
      // check if we have a valid argument
      if($arg_pos>-1 && $arg_pos<$count_args){
        //get the argument value
        $arg_value=func_get_arg($arg_pos);
        //replace {x} with the value of specific argument position
        self::$_str=str_replace($replace,$arg_value,self::$_str);
      }
    }
 
    return self::$_str;
 
  }
 
  /**
   * Format String using only str_replace
   *
   * @param String
   * @return String
   */
  public static function FormatSimpler($str){
 
    self::$_str=$str;
 
    //count arguments that our function received
    $count_args=func_num_args();
    //check if we have sufficient arguments
    if($count_args==1){return $str;}
 
    for($i=0;$i<$count_args-1;$i++){
      //get the argument value
      $arg_value=func_get_arg($i+1);
      //replace {$i} with the value of specific argument position
      self::$_str=str_replace("{{$i}}",$arg_value,self::$_str);
    }
 
    return self::$_str;
  }
 
}
 
?>

Example file:

<?php
 
include_once("class.String.php");
 
$str_format="
{5} {6} {0} {1} {4} {2},{3}
{6} {0} {1} {4} {2}.{3}
{5} {6} shadow of {6} day,{3}
{1} embrace {6} world in gray,{3}
{5} {6} {0} {1} {4} {2}.{3}";
 
$res[]=String::Format($str_format,"sun","will","you","<br/>","set for","and","the");
 
$res[]=String::FormatSimpler($str_format,"sun","will","you","<br/>","set for","and","the");
 
echo <<<OUTPUT
{$res[0]}
<br/>
{$res[1]}
OUTPUT;
?>

The examples above will output the following contents:

and the sun will set for you,
the sun will set for you.
and the shadow of the day,
will embrace the world in gray,
and the sun will set for you.

and the sun will set for you,
the sun will set for you.
and the shadow of the day,
will embrace the world in gray,
and the sun will set for you.

If you have any doubt or found any error, please drop me an email

15997

2008-06-25

mySnippets php

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