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Fetch a key from an associative array
(PHP 4, PHP 5)
Example 309. key() example<?phpRelated Examples ( Source code ) » key Examples ( Source code ) » Login ID Options Examples ( Source code ) » SAX parser in action Examples ( Source code ) » Create new table in MySQL Examples ( Source code ) » A Dynamic Bar Chart Examples ( Source code ) » Use this keyword to reference interal properties Examples ( Source code ) » Use this keyword Examples ( Source code ) » The Singleton Pattern Examples ( Source code ) » Singleton Pattern Demo Examples ( Source code ) » Looping Through the $GLOBALS Array Examples ( Source code ) » Save result of getdate() to an array Examples ( Source code ) » Extracting Parameters from Either a GET or POST Request Examples ( Source code ) » getdate() Seconds past the minutes Examples ( Source code ) » getdate() Minutes past the hour Examples ( Source code ) » getdate() Hours of theday Examples ( Source code ) » Day of the month getdate() Code Examples / Notes » keydanniel@t h e - police d'0't com
To get the key name by position from Array: <?php $myArray['name1']=3; $myArray['name2']=2; $myArray['name3']=1; echo($myArray[1]); /* return NULL */ /* isset($myArray[1]) return false; */ /* is_null($myArray[1]) return true; */ function KeyName($myArray,$pos) { // $pos--; /* uncomment the above line if you */ /* prefer position to start from 1 */ if ( ($pos < 0) || ( $pos >= count($myArray) ) ) return "NULL"; // set this any way you like reset($myArray); for($i = 0;$i < $pos; $i++) next($myArray); return key($myArray); } echo KeyName($myArray,1); // result: name2 echo KeyName($myArray,2); // result: name3 echo KeyName($myArray,3); // result: "NULL" ?> You can get any existing "key name" from array that is located at position $pos gived as second parameter. If no element is defined at given position the function will return the string "NULL". yarco dot w
Re: br_joris[at]hotmail[doth]com Do you really mean you want 2 keys point to 1 value? What you've written seems you want 1 key point to 2 values. But if you really want 2 keys point to 1 value, you could do the following: <?php $buf['key1'] = 'abc'; $buf['key2'] = & $buf['key1']; ?> php_notes
Note that key($array) returns NULL if $array's internal pointer goes past the end of the array. For example, the following code: <?php $arr = array( 'one' => '1', 'two' => '2', 'three' => '3', 'four' => '4', 'five' => '5'); for ($i = 0; $i < 10; $i++) { var_dump(key($arr)); next($arr); } ?> results in: string(3) "one" string(3) "two" string(5) "three" string(4) "four" string(4) "five" NULL NULL NULL NULL NULL shimon_d
make array[a][b] be array[b][a] function invertarray($a) { $o=array(); foreach($a as $k => $aa) { foreach($aa as $k1 => $v) { if(!isset($o[$k1]))$o[$k1]=array(); $o[$k1][$k]=$v; } } return $o; } mkeller
In the case key() does not give you back the key(myarray) but "0", try this: (Try this example without the line containing "end($myarray)" and you see my reason for this post...) for($i = 0; $i <= 10; $i++) { $myarray[] = 'content '.$i; end($myarray); echo (' key()='.key($myarray).' , content='.$myarray[$i]); } kajetan
I'm writing a forum and use an array to hold all the smiles. The keys in the array are the characters to write to get a smiley, and the data is the filename, like this $Smiles[':-)'] = 'smile.gif' To output all the smileys in a table with 3 columns, I wrote this code: $the_end = false; $s = reset($Smiles); $k = key($Smiles); while(!$the_end){ echo '<tr>'; for($i=0; $i<3; $i++){ echo '<td>'; if($the_end) echo ' '; else{ echo $k.'< br><img src="'. $s .'">'; $s = next($Smiles); if ($s==false) $the_end=true; else $k = key($Smiles); } echo "</td>\n"; } echo "</tr>\n"; } I had to write a space in the < br> tag in the code above, because the board did a line brake otherwise. danny
An auto incremental key value function, returning the key value: <? function add_key ($value, $array) // returns the key of the value added or existing already within the array { if (is_array ($array)) { if (!in_array ($value, $array)) { ksort ($array); end ($array); $key = key ($array) + 1; $array[$key] = $value; } else { $key = array_search ($value, $array); } } else { $key = 1; $array[$key] = $value; } return $key; } ?> php
A Method of Multi-Dimensionalizing an Associative Array (This idea was designed with Graphics (image filenames in mind): (A quick overview): While working on a rather large web application, I found that I needed a way to obtain "all" the details on images used by the application, these images (by filename) were stored in the configuration file, in the form of associative arrays. The following represents an example of how I tool those and converted them into multi-dimensional associative arrays. <code sample begin> do { $size = getImageSize($path.$myarray[key($myarray)]); if ($size[2] == '1') { $size[2] = 'gif'; } else if ($size[2] == '2') { $size[2] = 'jpg'; } else if ($size[2] == '3') { $size[2] = 'png'; } else if ($size[2] == '4') { $size[2] = 'swf'; } else { $size[2] = 'UNKNOWN'; } $myarray[key($myarray)] = Array($myarray[Key($myarray)],$size[0],$size[1],$size[2],$size[3]); } while (next($myarray)); </end code sample> The end result is an multi-dim. associative array which contains the values: $myarray["this"][0] = filename.gif $myarray["this"][1] = width $myarray["this"][2] = height $myarray["this"][3] = type (converted to the file extension.) $myarray["this"][4] = height=x width=x This may not be all that impressive to some, but it turned out to be very useful for me, so I thought I'd share, in addition, I think it gives a "very" good example of "a use" for the Key() function. Frankly, I was quite happy to discover this function, I can't count the number of times I "needed to use the key as a value". I hope you find this code useful. happy dot machine
$tab = array(); $tab[0] = 'php'; $tab[1] = '.'; $tab[2] = 'net'; // you will not enter the while // $key = 0, while will consider $key as false reset($tab); while ($key = key($tab) ) { echo $tab[$key]; next($tab); } // this will reset($tab); while (!is_null($key = key($tab) ) ) { echo $tab[$key]; next($tab); } // when key() can't return a 'key', it return NULL echo var_dump($key); 04-jun-2002 01:13
$input_array = array("FirSt" => 1, "SecOnd" => 4); print_r(array_change_key_case($input_array, CASE_UPPER)); |
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