Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <ul> <li>Changing Values: <ul> <li><a href="http://php.net/array_map" rel="noreferrer"><code>array_map</code></a> cannot change the values inside input array(s) while <a href="http://php.net/array_walk" rel="noreferrer"><code>array_walk</code></a> can; in particular, <a href="http://php.net/array_map" rel="noreferrer"><code>array_map</code></a> never changes its arguments.</li> </ul></li> <li>Array Keys Access: <ul> <li><a href="http://php.net/array_map" rel="noreferrer"><code>array_map</code></a> cannot operate with the array keys, <a href="http://php.net/array_walk" rel="noreferrer"><code>array_walk</code></a> can.</li> </ul></li> <li>Return Value: <ul> <li><a href="http://php.net/array_map" rel="noreferrer"><code>array_map</code></a> returns a new array, <a href="http://php.net/array_walk" rel="noreferrer"><code>array_walk</code></a> only returns <code>true</code>/<code>false</code>. Hence, if you don't want to create an array as a result of traversing one array, you should use <a href="http://php.net/array_walk" rel="noreferrer"><code>array_walk</code></a>.</li> </ul></li> <li>Iterating Multiple Arrays: <ul> <li><a href="http://php.net/array_map" rel="noreferrer"><code>array_map</code></a> also can receive an arbitrary number of arrays and it can iterate over them in parallel, while <a href="http://php.net/array_walk" rel="noreferrer"><code>array_walk</code></a> operates only on one.</li> </ul></li> <li>Passing Arbitrary Data to Callback: <ul> <li><a href="http://php.net/array_walk" rel="noreferrer"><code>array_walk</code></a> can receive an extra arbitrary parameter to pass to the callback. This mostly irrelevant since PHP 5.3 (when <a href="http://nl3.php.net/manual/en/functions.anonymous.php" rel="noreferrer">anonymous functions</a> were introduced).</li> </ul></li> <li>Length of Returned Array: <ul> <li>The resulting array of <code>array_map</code> has the same length as that of the largest input array; <code>array_walk</code> does not return an array but at the same time it cannot alter the number of elements of original array; <a href="http://php.net/array_filter" rel="noreferrer"><code>array_filter</code></a> picks only a subset of the elements of the array according to a filtering function. It does preserve the keys.</li> </ul></li> </ul> <p>Example:</p> <pre><code>&lt;pre&gt; &lt;?php $origarray1 = array(2.4, 2.6, 3.5); $origarray2 = array(2.4, 2.6, 3.5); print_r(array_map('floor', $origarray1)); // $origarray1 stays the same // changes $origarray2 array_walk($origarray2, function (&amp;$v, $k) { $v = floor($v); }); print_r($origarray2); // this is a more proper use of array_walk array_walk($origarray1, function ($v, $k) { echo "$k =&gt; $v", "\n"; }); // array_map accepts several arrays print_r( array_map(function ($a, $b) { return $a * $b; }, $origarray1, $origarray2) ); // select only elements that are &gt; 2.5 print_r( array_filter($origarray1, function ($a) { return $a &gt; 2.5; }) ); ?&gt; &lt;/pre&gt; </code></pre> <p>Result:</p> <pre><code>Array ( [0] =&gt; 2 [1] =&gt; 2 [2] =&gt; 3 ) Array ( [0] =&gt; 2 [1] =&gt; 2 [2] =&gt; 3 ) 0 =&gt; 2.4 1 =&gt; 2.6 2 =&gt; 3.5 Array ( [0] =&gt; 4.8 [1] =&gt; 5.2 [2] =&gt; 10.5 ) Array ( [1] =&gt; 2.6 [2] =&gt; 3.5 ) </code></pre>
    singulars
    1. This table or related slice is empty.
    1. PODifference between array_map, array_walk and array_filter
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USSalman A
    1. USArtefacto
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PODifference between array_map, array_walk and array_filter
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COCould you show them with an example please?
      singulars
      1. PO
      1. This table or related slice is empty.
    2. COGreat, thanks :)
      singulars
      1. PO
      1. This table or related slice is empty.
    3. COThe PHP manual says: "array_walk(): Only the values of the array may potentially be changed;"
      singulars
      1. PO
      1. USfeeela
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload