Alexander Stetsenko

Sometimes it could be necessary to get time with microseconds part. Especially it is good for something like logging when multiple entries are recorded per second and preferably to know how they are spread out.

At first glance everything looked very easy:

print date('Y-m-d H:i:s.u') ;

where u is microseconds.

However it turns out PHP manual has a tiny note which states

Since this [date()] function only accepts integer timestamps the u format character is only useful when using the date_format() function with user based timestamps created with date_create().

Which means that u kind of works but in case of calling within date() function the result is always .000000.

So the straight forward solution could be something like this:

print date('Y-m-d H:i:s') . substr((string)microtime(), 1, 8);

But the drawback of the solution above is two calls to the time related functions which potentially may cause some accuracy issues.

Thus even better solution is doing just one call of time function:

list($usec, $sec) = explode(' ', microtime());
print date('Y-m-d H:i:s', $sec) . $usec;

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While missing a C# method String.Format() I’ve found a similar function in PHP, i.e. sprintf(). But since this function is slightly different from String.Format() it is not obvious how to avoid duplicating the same parameters.

For instance how to re-write an example below without passing $url and $title twice.

$link = sprintf('<a href="%s" title="%s">%s</a> (%s)</li>',
              $url, $title, $title, $url);

The answer is less obvious compare to C# but still pretty handy:

$link = sprintf('<a href="%1$s" title="%2$s">%2$s</a> (%1$s)',
              $url, $title);

In both cases echo $link give the same output like:

<a href="http://www.google.com/" title="Google">Google</a> (http://www.google.com/)

but the second way makes the code more elegant .

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Even though it is a lot of talks about PHP 5.3 there are still many production environments which run PHP 5.1.*. As well as sometimes development servers are updated earlier than production ones for testing purposes. It may cause that some new PHP features will not work on production because of older version there.

One of the most common examples is ‘missing’ json_encode() function which became native with PHP 5.2.0 onward. Below is possible workaround while your production has not upgraded yet.

<?php
if (!function_exists('json_encode'))
{
  function json_encode($a=false)
  {
    if (is_null($a)) return 'null';
    if ($a === false) return 'false';
    if ($a === true) return 'true';
    if (is_scalar($a))
    {
      if (is_float($a))
      {
        // Always use "." for floats.
        return floatval(str_replace(",", ".", strval($a)));
      }
 
      if (is_string($a))
      {
        static $jsonReplaces = array(array("\\", "/", "\n", "\t", "\r", "\b", "\f", '"'), array('\\\\', '\\/', '\\n', '\\t', '\\r', '\\b', '\\f', '\"'));
        return '"' . str_replace($jsonReplaces[0], $jsonReplaces[1], $a) . '"';
      }
      else
        return $a;
    }
    $isList = true;
    for ($i = 0, reset($a); $i < count($a); $i++, next($a))
    {
      if (key($a) !== $i)
      {
        $isList = false;
        break;
      }
    }
    $result = array();
    if ($isList)
    {
      foreach ($a as $v) $result[] = json_encode($v);
      return '[' . join(',', $result) . ']';
    }
    else
    {
      foreach ($a as $k => $v) $result[] = json_encode($k).':'.json_encode($v);
      return '{' . join(',', $result) . '}';
    }
  }
}
?>

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