PHP Delete, convert, group, sort for arrays

This article mainly introduces PHP for the deletion of arrays, conversion, grouping, sorting, interested in the reference of friends, I hope to be helpful to everyone.

This article describes the PHP array operation class, as follows:

Class arrayhelper{/** * Remove blank elements from the array (including elements with only whitespace characters) * Usage: * @code php * $arr = Array (', ' test ', ');   * Arrayhelper::removeempty ($arr);   * * Dump ($arr); *//output will be only ' test ' * @endcode * * @param array $arr to be processed @param boolean $trim whether to call the trim function on an array element */Stati       C function Removeempty (& $arr, $trim = TRUE) {foreach ($arr as $key + $value) {if (Is_array ($value))      {Self::removeempty ($arr [$key]);        } else {$value = Trim ($value);        if ($value = = ") {unset ($arr [$key]);        } elseif ($trim) {$arr [$key] = $value;  }}}}/** * Returns all values of the specified key from a two-dimensional array * usage: * @code php * $rows = Array (* Array (' id ' = = 1, ' value ')   = ' 1-1 '), * array (' id ' = = 2, ' value ' = ' 2-1 '), *);   * $values = Arrayhelper::getcols ($rows, ' value ');   * * Dump ($values); *//output result is *//Array (*//' 1-1 ', *//' 2-1 ', *//) * @eNdcode * * @param array $arr Data source * @param string $col the key to query * * @return array containing all values of the specified key */static function    Getcols ($arr, $col) {$ret = array ();      foreach ($arr as $row) {if (Isset ($row [$col])) {$ret [] = $row [$col];  }} return $ret; }/** * Converts a two-dimensional array to HashMap and returns the result * Usage 1: * @code php * $rows = Array (* Array (' id ' = = 1, ' value ' = =   ' 1-1 '), * array (' id ' = = 2, ' value ' = ' 2-1 '), *);   * $hashmap = Arrayhelper::tohashmap ($rows, ' id ', ' value ');   * * Dump ($HASHMAP);  *//output result is *//Array (*///1 = ' 1-1 ', *//2 = ' 2-1 ', *//) * @endcode * * If omitted $valueField   parameter, the result of the conversion is an array that contains all the data for the item. * Usage 2: * @code php * $rows = Array (* Array (' id ' = + 1, ' value ' = ' 1-1 '), * array (' id ' = 2, ' Val   UE ' = ' 2-1 '), *);   * $hashmap = Arrayhelper::tohashmap ($rows, ' id ');   * * Dump ($HASHMAP); *//output result is *//Array (*//1 = array (' id ' = = 1, ' value ') = ' 1-1 '), *//2 = array (' id ' = + 2, ' value ' = ' 2-1 '), *//) * @endcode * * @param array $arr   Data source * @param string $keyField The value of the key to convert * @param string $valueField corresponding key value * * @return array converted HashMap style arrays    */static function Tohashmap ($arr, $keyField, $valueField = NULL) {$ret = array ();      if ($valueField) {foreach ($arr as $row) {$ret [$row [$keyField]] = $row [$valueField];      }} else {foreach ($arr as $row) {$ret [$row [$keyField]] = $row;  }} return $ret;   /** * Group A two-dimensional array by the value of the specified field * Usage: * @endcode * * @param array $arr Data source * @param string $keyField The key name to group by    * * @return The result of array grouping */static function groupBy ($arr, $keyField) {$ret = array ();      foreach ($arr as $row) {$key = $row [$keyField];    $ret [$key] = $row;  } return $ret; /** * Converts a planar two-dimensional array to a tree structure by the specified field * * * If you want to get a subtree of any node as root, you can use $refs parameters: * @code php * $refs= NULL;   * $tree = Arrayhelper::tree ($rows, ' id ', ' parent ', ' nodes ', $refs);   *//Output ID 3 node and all child nodes * $id = 3;   * Dump ($refs [$id]); * @endcode * * @param array $arr Data source * @param string $keyNodeId Node ID field name * @param string $keyParentId node parent ID field Name * @param string $keyChildrens The field name of the child node is saved * @param boolean $refs whether to include a node reference in the returned result * * return array of arrays of tree structure */static FU  Nction Totree ($arr, $keyNodeId, $keyParentId = ' parent_id ', $keyChildrens = ' childrens ', & $refs = NULL) {$refs =    Array ();      foreach ($arr as $offset = + $row) {$arr [$offset] [$keyChildrens] = array ();    $refs [$row [$keyNodeId]] =& $arr [$offset];    } $tree = Array ();      foreach ($arr as $offset = = $row) {$parentId = $row [$keyParentId];          if ($parentId) {if (!isset ($refs [$parentId])) {$tree [] =& $arr [$offset];        Continue        } $parent =& $refs [$parentId]; $parent [$keyChildrens] [] =& $arr [$offsET];      } else {$tree [] =& $arr [$offset];  }} return $tree;   }/** * Expands the tree array into a flat array * This method is the inverse of the trees () method. * * @param array $tree tree array * @param string $keyChildrens The key name that contains the child nodes * * @return Array expanded arrays */static function    Treetoarray ($tree, $keyChildrens = ' childrens ') {$ret = array (); if (Isset ($tree [$keyChildrens]) && is_array ($tree [$keyChildrens]) {foreach ($tree [$keyChildrens] as $chi      LD) {$ret = Array_merge ($ret, Self::treetoarray ($child, $keyChildrens));      } unset ($node [$keyChildrens]);    $ret [] = $tree;    } else {$ret [] = $tree;  } return $ret; /** * Sort by the specified key * * @endcode * * @param array $array the array to sort * @param string $keyname sort the key * @param int $dir Sort Direction * * @return Array sorted arrays */static function Sortbycol ($array, $keyname, $dir = SORT_ASC) {return sel  F::sortbymulticols ($array, array ($keyname = $dir)); }/** * A two-dimensional array in accordance with theMore than one column is sorted, like order by * in SQL statements usage: * @code php * $rows = Arrayhelper::sortbymulticols ($rows, Array (* ' Paren   T ' = = SORT_ASC, * ' name ' = + sort_desc, *)); * @endcode * * @param array $rowset arrays to sort * @param array $args sorted keys * * @return array sorted arrays */static FUNCT    Ion Sortbymulticols ($rowset, $args) {$sortArray = array ();    $sortRule = "; foreach ($args as $sortField + $sortDir) {foreach ($rowset as $offset + = $row) {$sortArray [$s      ortfield][$offset] = $row [$sortField]; } $sortRule. = ' $sortArray [\ '. $sortField. '\'], ' . $sortDir.    ', ';    } if (Empty ($sortArray) | | empty ($sortRule)) {return $rowset; } eval (' Array_multisort ('. $sortRule.    ' $rowset);  return $rowset; }}

Summary: the above is the entire content of this article, I hope to be able to help you learn.

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