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朋友问我一个PHP的问题,自己不会,所以跑来问大家!!
由于自己是搞JAVA的,但朋友问我一个PHP问题,内容如下:
<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->$testArr = array( 'php' => array( 'author' => 'allen', 'price' => 40, ), 'java' => array( 'author' => 'james', 'price' => 55, ), 'mysql' => array( 'author' => 'gates', 'price' => 30, ), 'html' => array( 'author' => 'bill', 'price' => 21, ));
uasort($testArr, create_function('$a,$b', 'return $a["price"]>$b["price"];'));//价格升序,降序改成<font color="#e78608">------解决方案--------------------</font><br>
$testArr = array( 'php' => array( 'author' => 'allen', 'price' => 40, ), 'java' => array( 'author' => 'james', 'price' => 55, ), 'mysql' => array( 'author' => 'gates', 'price' => 30, ), 'html' => array( 'author' => 'bill', 'price' => 21, ) ); function my_sort($a, $b){ return $a['price'] > $b['price']; } uasort($testArr, "my_sort"); print_r($testArr);?><br><font color="#e78608">------解决方案--------------------</font><br>
foreach ($testArr as $v) { $k[] = $v['price'];}array_multisort($k, SORT_DESC,$testArr);print_r(array_slice($testArr,0,3));<br><font color="#e78608">------解决方案--------------------</font><br>楼上几位共使用了两种类型的三种方法<br>对比如下
$testArr = array( 'php' => array( 'author' => 'allen', 'price' => 40, ), 'java' => array( 'author' => 'james', 'price' => 55, ), 'mysql' => array( 'author' => 'gates', 'price' => 30, ), 'html' => array( 'author' => 'bill', 'price' => 21, ));/*** 应用回调函数 ***/function func1($ar) { uasort($ar, create_function('$a,$b', 'return $a["price"]>$b["price"];'));//价格升序,降序改成 $row) { $price[$key] = $row['price']; } array_multisort($price, SORT_ASC,$ar);}/*** 应用 php5.3 闭包 ***/function func3($ar) { array_multisort(array_map(function($v){return $v['price'];},$ar),$ar);}check_speed(200, 'func2', $testArr);check_speed(200, 'func3', $testArr);check_speed(200, 'func1', $testArr);<div class="clear"> </div>