I'm sorting strings that are comprised of text and numbers.
I want the sort to sort the number parts as numbers, not alphanumeric.
For example I want: abc1def, ..., abc9def, abc10def
instead of: abc10def, abc1def, ..., abc9def
Does anyone know an algorithm for this (in particular in c++)
Thanks
I asked this exact question (although in Java) and got pointed to http://www.davekoelle.com/alphanum.html which has an algorithm and implementations of it in many languages.
Update 14 years later: Dave Koelle’s blog has gone off line and I can’t find his actual algorithm, but here’s an implementation.
https://github.com/cblanc/koelle-sort
Several natural sort implementations for C++ are available. A brief review:
natural_sort<> - based on Boost.Regex.
In my tests, it's roughly 20 times slower than other options.
Dirk Jagdmann's alnum.hpp, based on Dave Koelle's alphanum algorithm
Potential integer overlow issues for values over MAXINT
Martin Pool's natsort - written in C, but trivially usable from C++.
The only C/C++ implementation I've seen to offer a case insensitive version, which would seem to be a high priority for a "natural" sort.
Like the other implementations, it doesn't actually parse decimal points, but it does special case leading zeroes (anything with a leading 0 is assumed to be a fraction), which is a little weird but potentially useful.
PHP uses this algorithm.
This is known as natural sorting. There's an algorithm here that looks promising.
Be careful of problems with non-ASCII characters (see Jeff's blog entry on the subject).
Partially reposting my another answer:
bool compareNat(const std::string& a, const std::string& b){
if (a.empty())
return true;
if (b.empty())
return false;
if (std::isdigit(a[0]) && !std::isdigit(b[0]))
return true;
if (!std::isdigit(a[0]) && std::isdigit(b[0]))
return false;
if (!std::isdigit(a[0]) && !std::isdigit(b[0]))
{
if (a[0] == b[0])
return compareNat(a.substr(1), b.substr(1));
return (toUpper(a) < toUpper(b));
//toUpper() is a function to convert a std::string to uppercase.
}
// Both strings begin with digit --> parse both numbers
std::istringstream issa(a);
std::istringstream issb(b);
int ia, ib;
issa >> ia;
issb >> ib;
if (ia != ib)
return ia < ib;
// Numbers are the same --> remove numbers and recurse
std::string anew, bnew;
std::getline(issa, anew);
std::getline(issb, bnew);
return (compareNat(anew, bnew));
}
toUpper() function:
std::string toUpper(std::string s){
for(int i=0;i<(int)s.length();i++){s[i]=toupper(s[i]);}
return s;
}
Usage:
std::vector<std::string> str;
str.push_back("abc1def");
str.push_back("abc10def");
...
std::sort(str.begin(), str.end(), compareNat);
To solve what is essentially a parsing problem a state machine (aka finite state automaton) is the way to go. Dissatisfied with the above solutions i wrote a simple one-pass early bail-out algorithm that beats C/C++ variants suggested above in terms of performance, does not suffer from numerical datatype overflow errors, and is easy to modify to add case insensitivity if required.
sources can be found here
For those that arrive here and are already using Qt in their project, you can use the QCollator class. See this question for details.
Avalanchesort is a recursive variation of naturall sort, whiche merge runs, while exploring the stack of sorting-datas. The algorithim will sort stable, even if you add datas to your sorting-heap, while the algorithm is running/sorting.
The search-principle is simple. Only merge runs with the same rank.
After finding the first two naturell runs (rank 0), avalanchesort merge them to a run with rank 1. Then it call avalanchesort, to generate a second run with rank 1 and merge the two runs to a run with rank 2. Then it call the avalancheSort to generate a run with rank 2 on the unsorted datas....
My Implementation porthd/avalanchesort divide the sorting from the handling of the data using interface injection. You can use the algorithmn for datastructures like array, associative arrays or lists.
/**
* #param DataListAvalancheSortInterface $dataList
* #param DataRangeInterface $beginRange
* #param int $avalancheIndex
* #return bool
*/
public function startAvalancheSort(DataListAvalancheSortInterface $dataList)
{
$avalancheIndex = 0;
$rangeResult = $this->avalancheSort($dataList, $dataList->getFirstIdent(), $avalancheIndex);
if (!$dataList->isLastIdent($rangeResult->getStop())) {
do {
$avalancheIndex++;
$lastIdent = $rangeResult->getStop();
if ($dataList->isLastIdent($lastIdent)) {
$rangeResult = new $this->rangeClass();
$rangeResult->setStart($dataList->getFirstIdent());
$rangeResult->setStop($dataList->getLastIdent());
break;
}
$nextIdent = $dataList->getNextIdent($lastIdent);
$rangeFollow = $this->avalancheSort($dataList, $nextIdent, $avalancheIndex);
$rangeResult = $this->mergeAvalanche($dataList, $rangeResult, $rangeFollow);
} while (true);
}
return $rangeResult;
}
/**
* #param DataListAvalancheSortInterface $dataList
* #param DataRangeInterface $range
* #return DataRangeInterface
*/
protected function findRun(DataListAvalancheSortInterface $dataList,
$startIdent)
{
$result = new $this->rangeClass();
$result->setStart($startIdent);
$result->setStop($startIdent);
do {
if ($dataList->isLastIdent($result->getStop())) {
break;
}
$nextIdent = $dataList->getNextIdent($result->getStop());
if ($dataList->oddLowerEqualThanEven(
$dataList->getDataItem($result->getStop()),
$dataList->getDataItem($nextIdent)
)) {
$result->setStop($nextIdent);
} else {
break;
}
} while (true);
return $result;
}
/**
* #param DataListAvalancheSortInterface $dataList
* #param $beginIdent
* #param int $avalancheIndex
* #return DataRangeInterface|mixed
*/
protected function avalancheSort(DataListAvalancheSortInterface $dataList,
$beginIdent,
int $avalancheIndex = 0)
{
if ($avalancheIndex === 0) {
$rangeFirst = $this->findRun($dataList, $beginIdent);
if ($dataList->isLastIdent($rangeFirst->getStop())) {
// it is the last run
$rangeResult = $rangeFirst;
} else {
$nextIdent = $dataList->getNextIdent($rangeFirst->getStop());
$rangeSecond = $this->findRun($dataList, $nextIdent);
$rangeResult = $this->mergeAvalanche($dataList, $rangeFirst, $rangeSecond);
}
} else {
$rangeFirst = $this->avalancheSort($dataList,
$beginIdent,
($avalancheIndex - 1)
);
if ($dataList->isLastIdent($rangeFirst->getStop())) {
$rangeResult = $rangeFirst;
} else {
$nextIdent = $dataList->getNextIdent($rangeFirst->getStop());
$rangeSecond = $this->avalancheSort($dataList,
$nextIdent,
($avalancheIndex - 1)
);
$rangeResult = $this->mergeAvalanche($dataList, $rangeFirst, $rangeSecond);
}
}
return $rangeResult;
}
protected function mergeAvalanche(DataListAvalancheSortInterface $dataList, $oddListRange, $evenListRange)
{
$resultRange = new $this->rangeClass();
$oddNextIdent = $oddListRange->getStart();
$oddStopIdent = $oddListRange->getStop();
$evenNextIdent = $evenListRange->getStart();
$evenStopIdent = $evenListRange->getStop();
$dataList->initNewListPart($oddListRange, $evenListRange);
do {
if ($dataList->oddLowerEqualThanEven(
$dataList->getDataItem($oddNextIdent),
$dataList->getDataItem($evenNextIdent)
)) {
$dataList->addListPart($oddNextIdent);
if ($oddNextIdent === $oddStopIdent) {
$restTail = $evenNextIdent;
$stopTail = $evenStopIdent;
break;
}
$oddNextIdent = $dataList->getNextIdent($oddNextIdent);
} else {
$dataList->addListPart($evenNextIdent);
if ($evenNextIdent === $evenStopIdent) {
$restTail = $oddNextIdent;
$stopTail = $oddStopIdent;
break;
}
$evenNextIdent = $dataList->getNextIdent($evenNextIdent);
}
} while (true);
while ($stopTail !== $restTail) {
$dataList->addListPart($restTail);
$restTail = $dataList->getNextIdent($restTail);
}
$dataList->addListPart($restTail);
$dataList->cascadeDataListChange($resultRange);
return $resultRange;
}
}
My algorithm with test code of java version. If you want to use it in your project you can define a comparator yourself.
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.function.Consumer;
public class FileNameSortTest {
private static List<String> names = Arrays.asList(
"A__01__02",
"A__2__02",
"A__1__23",
"A__11__23",
"A__3++++",
"B__1__02",
"B__22_13",
"1_22_2222",
"12_222_222",
"2222222222",
"1.sadasdsadsa",
"11.asdasdasdasdasd",
"2.sadsadasdsad",
"22.sadasdasdsadsa",
"3.asdasdsadsadsa",
"adsadsadsasd1",
"adsadsadsasd10",
"adsadsadsasd3",
"adsadsadsasd02"
);
public static void main(String...args) {
List<File> files = new ArrayList<>();
names.forEach(s -> {
File f = new File(s);
try {
if (!f.exists()) {
f.createNewFile();
}
files.add(f);
} catch (IOException e) {
e.printStackTrace();
}
});
files.sort(Comparator.comparing(File::getName));
files.forEach(f -> System.out.print(f.getName() + " "));
System.out.println();
files.sort(new Comparator<File>() {
boolean caseSensitive = false;
int SPAN_OF_CASES = 'a' - 'A';
#Override
public int compare(File left, File right) {
char[] csLeft = left.getName().toCharArray(), csRight = right.getName().toCharArray();
boolean isNumberRegion = false;
int diff=0, i=0, j=0, lenLeft=csLeft.length, lenRight=csRight.length;
char cLeft = 0, cRight = 0;
for (; i<lenLeft && j<lenRight; i++, j++) {
cLeft = getCharByCaseSensitive(csLeft[i]);
cRight = getCharByCaseSensitive(csRight[j]);
boolean isNumericLeft = isNumeric(cLeft), isNumericRight = isNumeric(cRight);
if (isNumericLeft && isNumericRight) {
// Number start!
if (!isNumberRegion) {
isNumberRegion = true;
// Remove prefix '0'
while (i < lenLeft && cLeft == '0') i++;
while (j < lenRight && cRight == '0') j++;
if (i == lenLeft || j == lenRight) break;
}
// Diff start: calculate the diff value.
if (cLeft != cRight && diff == 0)
diff = cLeft - cRight;
} else {
if (isNumericLeft != isNumericRight) {
// One numeric and one char.
if (isNumberRegion)
return isNumericLeft ? 1 : -1;
return cLeft - cRight;
} else {
// Two chars: if (number) diff don't equal 0 return it.
if (diff != 0)
return diff;
// Calculate chars diff.
diff = cLeft - cRight;
if (diff != 0)
return diff;
// Reset!
isNumberRegion = false;
diff = 0;
}
}
}
// The longer one will be put backwards.
return (i == lenLeft && j == lenRight) ? cLeft - cRight : (i == lenLeft ? -1 : 1) ;
}
private boolean isNumeric(char c) {
return c >= '0' && c <= '9';
}
private char getCharByCaseSensitive(char c) {
return caseSensitive ? c : (c >= 'A' && c <= 'Z' ? (char) (c + SPAN_OF_CASES) : c);
}
});
files.forEach(f -> System.out.print(f.getName() + " "));
}
}
The output is,
1.sadasdsadsa 11.asdasdasdasdasd 12_222_222 1_22_2222 2.sadsadasdsad 22.sadasdasdsadsa 2222222222 3.asdasdsadsadsa A__01__02 A__11__23 A__1__23 A__2__02 A__3++++ B__1__02 B__22_13 adsadsadsasd02 adsadsadsasd1 adsadsadsasd10 adsadsadsasd3
1.sadasdsadsa 1_22_2222 2.sadsadasdsad 3.asdasdsadsadsa 11.asdasdasdasdasd 12_222_222 22.sadasdasdsadsa 2222222222 A__01__02 A__1__23 A__2__02 A__3++++ A__11__23 adsadsadsasd02 adsadsadsasd1 adsadsadsasd3 adsadsadsasd10 B__1__02 B__22_13
Process finished with exit code 0
// -1: s0 < s1; 0: s0 == s1; 1: s0 > s1
static int numericCompare(const string &s0, const string &s1) {
size_t i = 0, j = 0;
for (; i < s0.size() && j < s1.size();) {
string t0(1, s0[i++]);
while (i < s0.size() && !(isdigit(t0[0]) ^ isdigit(s0[i]))) {
t0.push_back(s0[i++]);
}
string t1(1, s1[j++]);
while (j < s1.size() && !(isdigit(t1[0]) ^ isdigit(s1[j]))) {
t1.push_back(s1[j++]);
}
if (isdigit(t0[0]) && isdigit(t1[0])) {
size_t p0 = t0.find_first_not_of('0');
size_t p1 = t1.find_first_not_of('0');
t0 = p0 == string::npos ? "" : t0.substr(p0);
t1 = p1 == string::npos ? "" : t1.substr(p1);
if (t0.size() != t1.size()) {
return t0.size() < t1.size() ? -1 : 1;
}
}
if (t0 != t1) {
return t0 < t1 ? -1 : 1;
}
}
return i == s0.size() && j == s1.size() ? 0 : i != s0.size() ? 1 : -1;
}
I am not very sure if it is you want, anyway, you can have a try:-)
I have some entries in my app which contain some numbers and I have a button that when I click on the button it adds one unit to the number in the entry that is focused, but the problem is that when i click the button, the entry loses the focus and keyboard disappears, although I want the entry to be focused, I found a solution for Android, but couldn't find anything for iOS!!
Does anybody know what to do? I don't want the entry to lose focus
Update:
private void StepUpButton_Clicked(object sender, EventArgs e)
{
double value;
for (int i = 0; i < 30; i++)
{
if (GetEntries(i).IsFocused)
{
if (String.IsNullOrEmpty(GetEntries(i).Text) || GetEntries(i).Text.Equals("-"))
{
value = 0.00;
}
else
{
value = Convert.ToDouble(GetEntries(i).Text);
}
for (int j = 0; j < 10; j++)
{
if (GetEntries(i) == GetVa1ToVb1Amp(j))
{
GetVa1ToVb1Amp(j).Text = controller.StepUpClicked(0, value).ToString("F2");
}
if (GetEntries(i) == GetIa1ToIb3Amp(j))
{
GetIa1ToIb3Amp(j).Text = controller.StepUpClicked(1, value).ToString("F3");
}
if (GetEntries(i) == GetVa1ToIb3Phase(j))
{
GetVa1ToIb3Phase(j).Text = controller.StepUpClicked(2, value).ToString("F2");
}
if (GetEntries(i) == GetVa1ToIb3Freq(j))
{
GetVa1ToIb3Freq(j).Text = controller.StepUpClicked(3, value).ToString("F3");
}
}
}
}
}
Given a linked List $link1, with elements (a->b->c->d->e->f->g->h->i->j), we need to reverse the linked list provided that the reversing will be done in a manner like -
Reverse 1st element (a)
Reverse next 2 elements (a->c->b)
Reverse next 3 elements (a->c->b->f->e->d)
Reverse next 4 elements (a->c->b->f->e->d->j->i->h->g)
....
....
I have created below code in PHP to solve this problem
Things I need -
I need to calculate the time complexity of reverseLinkedList function below.
Need to know if we can optimize reverseLinkedList function to reduce time complexity.
-
class ListNode
{
public $data;
public $next;
function __construct($data)
{
$this->data = $data;
$this->next = NULL;
}
function read_node()
{
return $this->data;
}
}
class LinkList
{
private $first_node;
private $last_node;
private $count;
function __construct()
{
$this->first_node = NULL;
$this->last_node = NULL;
$this->count = 0;
}
function size()
{
return $this->count;
}
public function read_list()
{
$listData = array();
$current = $this->first_node;
while($current != NULL)
{
echo $current->read_node().' ';
$current = $current->next;
}
}
public function reverse_list()
{
if(($this->first_node != NULL)&&($this->first_node->next != NULL))
{
$current = $this->first_node;
$new = NULL;
while ($current != NULL)
{
$temp = $current->next;
$current->next = $new;
$new = $current;
$current = $temp;
}
$this->first_node = $new;
}
}
public function read_node($position)
{
if($position <= $this->count)
{
$current = $this->first_node;
$pos = 1;
while($pos != $position)
{
if($current->next == NULL)
return null;
else
$current = $current->next;
$pos++;
}
return $current->data;
}
else
return NULL;
}
public function insert($data)
{
$new_node = new ListNode($data);
if($this->first_node != NULL)
{
$this->last_node->next = $new_node;
$new_node->next = NULL;
$this->last_node = &$new_node;
$this->count++;
}
else
{
$new_node->next = $this->first_node;
$this->first_node = &$new_node;
if($this->last_node == NULL)
$this->last_node = &$new_node;
$this->count++;
}
}
}
//Create linked list
$link1 = new LinkList();
//Insert elements
$link1->insert('a');
$link1->insert('b');
$link1->insert('c');
$link1->insert('d');
$link1->insert('e');
$link1->insert('f');
$link1->insert('g');
$link1->insert('h');
$link1->insert('i');
$link1->insert('j');
echo "<b>Input :</b><br>";
$link1->read_list();
//function to reverse linked list in specified manner
function reverseLinkedList(&$link1)
{
$size= $link1->size();
if($size>2)
{
$link2=new LinkList();
$link2->insert($link1->read_node(1));
$elements_covered=1;
//reverse
$rev_size=2;
while($elements_covered<$size)
{
$start=$elements_covered+1;
$temp_link = new LinkList();
$temp_link->insert($link1->read_node($start));
for($i=1;$i<$rev_size;$i++)
{
$temp_link->insert($link1->read_node(++$start));
}
$temp_link->reverse_list();
$temp_size=$temp_link->size();
$link2_size=$link2->size();
for($i=1;$i<=$temp_size;$i++)
{
$link2->insert($temp_link->read_node($i));
++$elements_covered;
++$link2_size;
}
++$rev_size;
}
///reverse
//Flip the linkedlist
$link1=$link2;
}
}
///function to reverse linked list in specified manner
//Reverse current linked list $link1
reverseLinkedList($link1);
echo "<br><br><b>Output :</b><br>";
$link1->read_list();
It's O(n)...just one traversal.
And secondly, here tagging it in language is not necessary.
I have provided a Pseudocode here for your reference:
current => head_ref
prev => NULL;
current => head_ref;
next => null;
while (current != NULL)
{
next = current->next;
current->next = prev;
prev = current;
current = next;
}
*head_ref = prev;
I am building an AppWorld sort of thing in blackberry.I have Categories,sub categories and apps within.I want to do in-app download,but as of now i am calling the browser and passing the url and downloading of the content happens.How to make in-app download or download from within my app just like the AppWorld of blackberry.
YOu need to use code module manager API to download and install applications.
Code in bits and pieces
_moduleGroup = new CodeModuleGroup(appVendorName);
_moduleGroup.setVersion(JADParser.getValue("MIDlet-Version"));
_moduleGroup.setVendor(vendorName);
_moduleGroup.setFriendlyName(appName);
_moduleGroup.setDescription(JADParser.getValue("MIDlet-Description"));
String dependency = JADParser.getValue("RIM-COD-Module-Dependencies");
if (dependency != null)
{
dependency = dependency.trim();
String[] dependencyList = vStringUtils.split(dependency, ',');
for (int i = 0; i < dependencyList.length; i++)
{
_moduleGroup.addDependency(dependencyList[i]);
}
}
for (i = 0; i < count; i++)
{
if (!writeCODFile(getCodFileData(i), getCodFileName(i)))
{
throw new Exception();
}
}
private boolean writeCODFile(byte[] data, String fileName)
{
boolean isSuccess = true;
int moduleId = 0;
if (data.length > MODULE_SIZE_LIMIT)
{
moduleId = CodeModuleManager.createNewModule(data.length, data, MODULE_SIZE_LIMIT);
isSuccess = CodeModuleManager.writeNewModule(moduleId, MODULE_SIZE_LIMIT, data, MODULE_SIZE_LIMIT, data.length - MODULE_SIZE_LIMIT);
}
else
{
moduleId = CodeModuleManager.createNewModule(data.length, data, data.length);
}
if (moduleId > 0 && isSuccess)
{
int ret = CodeModuleManager.saveNewModule(moduleId, true, _transactionId);
if (ret == CodeModuleManager.CMM_OK_MODULE_OVERWRITTEN || ret == CodeModuleManager.CMM_OK)
{
return true;
}
}
return false;
}
Hi I Got a notnull function for a text field as below
private function valStringNotNull( val:String ) :Boolean
{
if ( String(val).length <= 0 )
{
_errorCode = "StringNull";
return false;
}
_errorCode = "NoError";
return true;
}
and this function is being called here
var pCnt:Number = 0;
_validateParams[pCnt++] = { type: "notNull", input: win.firstNameInput , isSendData:true, dataName:"firstName"};
_validateParams[pCnt++] = { type: "notNull", input: win.lastNameInput, isSendData:true, dataName:"lastName"};
_validateParams[pCnt++] = { type: "noValidation", input: roleCombo, isSendData:true, dataName:"role" };
Selection.setFocus(win.firstNameInput);
and for the not null I defined this way
private function validateCases ( param:Object ) :Boolean
{
_errorObj = param.input || param.input1;
switch( param.type )
{
case "notNull":
return valStringNotNull( param.input.text );
break;
}
}
but as you see as I defined the length should be greater than zero its taking even a space as an input and displaying blank white space in my text field so I got a trim function as below
public function ltrim(input:String):String
{
var size:Number = input.length;
for(var i:Number = 0; i < size; i++)
{
if(input.charCodeAt(i) > 32)
{
return input.substring(i);
}
}
return "";
}
and I need to call this trim function before my not null function so that it trims off all the leftside white space but as I am very new to flash can some one help me how to keep this trim function before the notnull function.Can some one please help me with this please
A function to replace any string as you wish, just combine them!
String.prototype.replace = function(searchStr, replaceStr):String
{
return this.split(searchStr).join(replaceStr);
};
Example:
// initial string with a placeholder
var str:String = '$person is welcome';
// replace $person with 'Flash developer' and trace it
var replacedStr:String = str.replace('$person','Flash developer');
trace(replacedStr);
Why not just change valStringNotNull() as follows?
private function valStringNotNull( val:String ) :Boolean
{
if ( String(ltrim(val)).length <= 0 )
{
_errorCode = "StringNull";
return false;
}
_errorCode = "NoError";
return true;
}