I have a dictionary like this (sample data thus it doesn't make sense):
Dictionary<char, string[]> codes = new Dictionary<char, string[]>();
string[] is an array of possible replacements for the Dictionary's key.
Filling up the dictionary with some sample data...
codes.Add("A", new string[] {"噅噅", "裧", "頖", "11"});
codes.Add("B", new string[] {"垥", "2", "鉠"});
codes.Add("C", new string[] {"33", "韎"});
codes.Add("D", new string[] {"櫋", "緟", "嘕", "鈖", "灡", "犅"});
...
codes.Add("T", new string[] {"濇", "汫", "岕", "5"});
...
Now lets "encode" the following word:
char[] charArray = "act".ToCharArray();
foreach (char c in charArray) {
string[] replacements = codes[c].Where(x => !String.IsNullOrEmpty(x)).ToArray();//removing empty elements
...
}
I cannot wrap my head now on what to do next, I want to have a list of all possible combinations, it should return a list like this (for the word "act"):
噅噅韎5
裧33濇
裧33汫
裧33岕
裧335
裧韎濇
裧韎汫
裧韎岕
...
Can't show all combinations because of stackoverflow's spam filter...
The post title is misleading. If I understand correctly, you want to generate all the combinations using the codes as input char replacements.
I have answered a similar question (String combinations with multi-character replacement), however due to string[] part I cannot reuse directly the handy code from Looking at each combination in jagged array, so instead I'll just utilize the same algorithm for your case:
public static class Algorithms
{
public static IEnumerable<string> GetCombinations(this string input, Dictionary<char, string[]> replacements)
{
var map = new string[input.Length][];
for (int i = 0; i < map.Length; i++)
{
var c = input[i];
string[] r;
map[i] = replacements.TryGetValue(c, out r)
&& (r = r.Where(s => !string.IsNullOrEmpty(s)).ToArray()).Length > 0 ?
r : new string[] { c.ToString() };
}
int maxLength = map.Sum(output => output.Max(s => s.Length));
var buffer = new char[maxLength];
int length = 0;
var indices = new int[input.Length];
for (int pos = 0, index = 0; ;)
{
for (; pos < input.Length; pos++, index = 0)
{
indices[pos] = index;
foreach (var c in map[pos][index])
buffer[length++] = c;
}
yield return new string(buffer, 0, length);
do
{
if (pos == 0) yield break;
index = indices[--pos];
length -= map[pos][index].Length;
}
while (++index >= map[pos].Length);
}
}
}
Test:
var codes = new Dictionary<char, string[]>();
codes.Add('A', new string[] { "噅噅", "裧", "頖", "11" });
codes.Add('B', new string[] { "垥", "2", "鉠" });
codes.Add('C', new string[] { "33", "韎" });
codes.Add('D', new string[] { "櫋", "緟", "嘕", "鈖", "灡", "犅" });
//...
codes.Add('T', new string[] { "濇", "汫", "岕", "5" });
//...
var test = "ACT".GetCombinations(codes).ToList();
I am experiencing an Error within nouns[i] = SearchKeywords(words, sentences); every time I run my program. What should I do?
*I edited to include the SearchKeywords method. I am trying to find all words that have "a" and "an" before them.
Error is,
Error Cannot implicitly convert type 'string[]' to 'string'
string[] SearchKeywords(List<string> keywords, string[] sentence){
int[] location = new int[sentence.Length];
foreach (string word in keywords)
{
for (int i = 0; i < sentence.Length;i++ )
{
string[] nouns = new string[i];
if (String.IsNullOrEmpty(sentence[i]))
{
return null;
}
else
{
location[i] = sentence[i].IndexOf(word);
nouns[i] = sentence[i].Substring(location[i]);
if (nouns[i].Contains(word)) return nouns;
}
}
}
return sentence;
string[] checkForIndefinite()
{
string input = txtEntry.Text;
string text = lbltxtOutput.Text;
Tools tool = new Tools();
List<string> words = new List<string>();
words.Add("an");
words.Add("a");
foreach(string sentence in GetWords(text))
{
for (int i = 0; i < sentence.Length; i++)
{
string[] nouns = new string[i];
string[] sentences = new string[i];
sentences[i] = sentence;
**nouns[i] = SearchKeywords(words, sentences);**
return nouns;
}
}
return null;
}
It seems to me that this is what you need:
string[] SearchKeywords(List<string> keywords, string[] sentence)
{
return
sentence
.Zip(sentence.Skip(1), (w0, w1) => new { w0, w1 })
.Where(ww => keywords.Contains(ww.w0))
.Select(ww => ww.w1)
.ToArray();
}
string[] checkForIndefinite()
{
var input = txtEntry.Text;
var text = lbltxtOutput.Text;
var words = new List<string>() { "an", "a" };
return SearchKeywords(words, GetWords(text));
}
The output of the SearchKeywords function is an string[] and the nouns[i] is a string and simply you cannot assign and string[] value to a string. So You may what to try something like this:
List<string> nouns = new List<string>();
//foreach loop
// for loop
nouns.AddRange(SearchKeywords(words, sentences));
using System;
using System.Security.Cryptography;
using System.Text;
using System.Collections.Generic;
public class Program
{
public static void Main()
{
string[] indefinites = checkForIndefinite();
foreach (string s in indefinites)
{
Console.WriteLine(s);
}
}
static string[] SearchKeywords(List<string> keywords, string sentence)
{
if (String.IsNullOrEmpty(sentence))
{
return null;
}
List<string> nouns = new List<string>();
string[] words = sentence.Split(' ');
foreach (string keyword in keywords)
{
for (int i = 0; i < words.Length; i++ )
{
if (words[i] == keyword)
{
if (i+1 < words.Length && !nouns.Contains(words[i+1]))
{
nouns.Add(words[i+1]);
}
}
}
}
return nouns.ToArray();
}
static string[] checkForIndefinite()
{
string sentence = "This is not an interesting sentence to use to test a program";
string text = string.Empty;
List<string> words = new List<string>();
words.Add("an");
words.Add("a");
return SearchKeywords(words, sentence);
}
}
This compiles and returns the following:
interesting
program
seriously need some guideline on string sorting methodology. Perhaps, if able to provide some sample code would be a great help. This is not a homework. I would need this sorting method for concurrently checking multiple channel names and feed the channel accordingly based on the sort name/string result.
Firstly I would have the string array pattern something like below:
string[] strList1 = new string[] {"TDC1ABF", "TDC1ABI", "TDC1ABO" };
string[] strList2 = new string[] {"TDC2ABF", "TDC2ABI", "TDC2ABO"};
string[] strList3 = new string[] {"TDC3ABF", "TDC3ABO","TDC3ABI"}; //2nd and 3rd element are swapped
I would like to received a string[] result like below:
//result1 = "TDC1ABF , TDC2ABF, TDC3ABF"
//result2 = "TDC1ABI , TDC2ABI, TDC3ABI"
//result3 = "TDC1ABO , TDC2ABO, TDC3ABO"
Ok, here is my idea of doing the sorting.
First, each of the strList sort keyword *ABF.
Then, put all the strings with *ABF into result array.
Finally do Order sort to have the string array align into TDC1ABF, TDC2ABF, TDC3ABF accordingly.
Do the same thing for the other string array inside a loop.
So, my problem is.. how to search *ABF within a string inside a string array?
static void Main()
{
var strList1 = new[] { "TDC1ABF", "TDC1ABI", "TDC1ABO" };
var strList2 = new[] { "TDC2ABF", "TDC2ABI", "TDC2ABO" };
var strList3 = new[] { "TDC3ABF", "TDC3ABO", "TDC3ABI" };
var allItems = strList1.Concat(strList2).Concat(strList3);
var abfItems = allItems.Where(item => item.ToUpper().EndsWith("ABF"))
.OrderBy(item => item);
var abiItems = allItems.Where(item => item.ToUpper().EndsWith("ABI"))
.OrderBy(item => item);
var aboItems = allItems.Where(item => item.ToUpper().EndsWith("ABO"))
.OrderBy(item => item);
}
If you do something like this then you can compare all the sums and arrange them in order. The lower sums are the ones closer to 1st and the higher are the ones that are farther down.
static void Main(string[] args)
{
string[] strList1 = new string[] { "TDC1ABF", "TDC1ABI", "TDC1ABO" };
string[] strList2 = new string[] { "TDC2ABF", "TDC2ABI", "TDC2ABO" };
string[] strList3 = new string[] { "TDC3ABF", "TDC3ABO", "TDC3ABI" };
arrange(strList1);
arrange(strList2);
arrange(strList3);
}
public static void arrange(string[] list)
{
Console.WriteLine("OUT OF ORDER");
foreach (string item in list)
{
Console.WriteLine(item);
}
Console.WriteLine();
for (int x = 0; x < list.Length - 1; x++)
{
char[] temp = list[x].ToCharArray();
char[] temp1 = list[x + 1].ToCharArray();
int sum = 0;
foreach (char letter in temp)
{
sum += (int)letter; //This adds the ASCII value of each char
}
int sum2 = 0;
foreach (char letter in temp1)
{
sum2 += (int)letter; //This adds the ASCII value of each char
}
if (sum > sum2)
{
string swap1 = list[x];
list[x] = list[x + 1];
list[x + 1] = swap1;
}
}
Console.WriteLine("IN ORDER");
foreach (string item in list)
{
Console.WriteLine(item);
}
Console.WriteLine();
Console.ReadLine();
}
If the arrays are guaranteed to have as many elements as there are arrays then you could sort the individual arrays first, dump the sorted arrays into an nxn array and then transpose the matrix.
I have an ArrayList[] myList and I am trying to create a list of all the permutations of the values in the arrays.
EXAMPLE: (all values are strings)
myList[0] = { "1", "5", "3", "9" };
myList[1] = { "2", "3" };
myList[2] = { "93" };
The count of myList can be varied so its length is not known beforehand.
I would like to be able to generate a list of all the permutations similar to the following (but with some additional formatting).
1 2 93
1 3 93
5 2 93
5 3 93
3 2 93
3 3 93
9 2 93
9 3 93
Does this make sense of what I am trying to accomplish? I can't seem to come up with a good method for doing this, (if any).
Edit:
I am not sure if recursion would interfere with my desire to format the output in my own manner. Sorry I did not mention before what my formatting was.
I want to end up building a string[] array of all the combinations that follows the format like below:
for the "1 2 93" permutation
I want the output to be "val0=1;val1=2;val2=93;"
I will experiment with recursion for now. Thank you DrJokepu
I'm surprised nobody posted the LINQ solution.
from val0 in new []{ "1", "5", "3", "9" }
from val1 in new []{ "2", "3" }
from val2 in new []{ "93" }
select String.Format("val0={0};val1={1};val2={2}", val0, val1, val2)
Recursive solution
static List<string> foo(int a, List<Array> x)
{
List<string> retval= new List<string>();
if (a == x.Count)
{
retval.Add("");
return retval;
}
foreach (Object y in x[a])
{
foreach (string x2 in foo(a + 1, x))
{
retval.Add(y.ToString() + " " + x2.ToString());
}
}
return retval;
}
static void Main(string[] args)
{
List<Array> myList = new List<Array>();
myList.Add(new string[0]);
myList.Add(new string[0]);
myList.Add(new string[0]);
myList[0] = new string[]{ "1", "5", "3", "9" };
myList[1] = new string[] { "2", "3" };
myList[2] = new string[] { "93" };
foreach (string x in foo(0, myList))
{
Console.WriteLine(x);
}
Console.ReadKey();
}
Note that it would be pretty easy to return a list or array instead of a string by changing the return to be a list of lists of strings and changing the retval.add call to work with a list instead of using concatenation.
How it works:
This is a classic recursive algorithm. The base case is foo(myList.Count, myList), which returns a List containing one element, the empty string. The permutation of a list of n string arrays s1, s2, ..., sN is equal to every member of sA1 prefixed to the permutation of n-1 string arrays, s2, ..., sN. The base case is just there to provide something for each element of sN to be concatenated to.
I recently ran across a similar problem in a project of mine and stumbled on this question. I needed a non-recursive solution that could work with lists of arbitrary objects. Here's what I came up with. Basically I'm forming a list of enumerators for each of the sub-lists and incrementing them iteratively.
public static IEnumerable<IEnumerable<T>> GetPermutations<T>(IEnumerable<IEnumerable<T>> lists)
{
// Check against an empty list.
if (!lists.Any())
{
yield break;
}
// Create a list of iterators into each of the sub-lists.
List<IEnumerator<T>> iterators = new List<IEnumerator<T>>();
foreach (var list in lists)
{
var it = list.GetEnumerator();
// Ensure empty sub-lists are excluded.
if (!it.MoveNext())
{
continue;
}
iterators.Add(it);
}
bool done = false;
while (!done)
{
// Return the current state of all the iterator, this permutation.
yield return from it in iterators select it.Current;
// Move to the next permutation.
bool recurse = false;
var mainIt = iterators.GetEnumerator();
mainIt.MoveNext(); // Move to the first, succeeds; the main list is not empty.
do
{
recurse = false;
var subIt = mainIt.Current;
if (!subIt.MoveNext())
{
subIt.Reset(); // Note the sub-list must be a reset-able IEnumerable!
subIt.MoveNext(); // Move to the first, succeeds; each sub-list is not empty.
if (!mainIt.MoveNext())
{
done = true;
}
else
{
recurse = true;
}
}
}
while (recurse);
}
}
You could use factoradics to generate the enumeration of permutations. Try this article on MSDN for an implementation in C#.
This will work no matter how many arrays you add to your myList:
static void Main(string[] args)
{
string[][] myList = new string[3][];
myList[0] = new string[] { "1", "5", "3", "9" };
myList[1] = new string[] { "2", "3" };
myList[2] = new string[] { "93" };
List<string> permutations = new List<string>(myList[0]);
for (int i = 1; i < myList.Length; ++i)
{
permutations = RecursiveAppend(permutations, myList[i]);
}
//at this point the permutations variable contains all permutations
}
static List<string> RecursiveAppend(List<string> priorPermutations, string[] additions)
{
List<string> newPermutationsResult = new List<string>();
foreach (string priorPermutation in priorPermutations)
{
foreach (string addition in additions)
{
newPermutationsResult.Add(priorPermutation + ":" + addition);
}
}
return newPermutationsResult;
}
Note that it's not really recursive. Probably a misleading function name.
Here is a version that adheres to your new requirements. Note the section where I output to console, this is where you can do your own formatting:
static void Main(string[] args)
{
string[][] myList = new string[3][];
myList[0] = new string[] { "1", "5", "3", "9" };
myList[1] = new string[] { "2", "3" };
myList[2] = new string[] { "93" };
List<List<string>> permutations = new List<List<string>>();
foreach (string init in myList[0])
{
List<string> temp = new List<string>();
temp.Add(init);
permutations.Add(temp);
}
for (int i = 1; i < myList.Length; ++i)
{
permutations = RecursiveAppend(permutations, myList[i]);
}
//at this point the permutations variable contains all permutations
foreach (List<string> list in permutations)
{
foreach (string item in list)
{
Console.Write(item + ":");
}
Console.WriteLine();
}
}
static List<List<string>> RecursiveAppend(List<List<string>> priorPermutations, string[] additions)
{
List<List<string>> newPermutationsResult = new List<List<string>>();
foreach (List<string> priorPermutation in priorPermutations)
{
foreach (string addition in additions)
{
List<string> priorWithAddition = new List<string>(priorPermutation);
priorWithAddition.Add(addition);
newPermutationsResult.Add(priorWithAddition);
}
}
return newPermutationsResult;
}
What you are asking for is called the Cartesian Product. Once you know what its called, there are several similar questions on Stack Overflow. They all seem to end up pointing to an answer which ended up written as a blog post:
http://blogs.msdn.com/b/ericlippert/archive/2010/06/28/computing-a-cartesian-product-with-linq.aspx
Non-recursive solution:
foreach (String s1 in array1) {
foreach (String s2 in array2) {
foreach (String s3 in array3) {
String result = s1 + " " + s2 + " " + s3;
//do something with the result
}
}
}
Recursive solution:
private ArrayList<String> permute(ArrayList<ArrayList<String>> ar, int startIndex) {
if (ar.Count == 1) {
foreach(String s in ar.Value(0)) {
ar.Value(0) = "val" + startIndex + "=" + ar.Value(0);
return ar.Value(0);
}
ArrayList<String> ret = new ArrayList<String>();
ArrayList<String> tmp1 ar.Value(0);
ar.remove(0);
ArrayList<String> tmp2 = permute(ar, startIndex+1);
foreach (String s in tmp1) {
foreach (String s2 in tmp2) {
ret.Add("val" + startIndex + "=" + s + " " + s2);
}
}
return ret;
}
Here is a generic recursive function that I wrote (and an overload that may be convenient to call):
Public Shared Function GetCombinationsFromIEnumerables(ByRef chain() As Object, ByRef IEnumerables As IEnumerable(Of IEnumerable(Of Object))) As List(Of Object())
Dim Combinations As New List(Of Object())
If IEnumerables.Any Then
For Each v In IEnumerables.First
Combinations.AddRange(GetCombinationsFromIEnumerables(chain.Concat(New Object() {v}).ToArray, IEnumerables.Skip(1)).ToArray)
Next
Else
Combinations.Add(chain)
End If
Return Combinations
End Function
Public Shared Function GetCombinationsFromIEnumerables(ByVal ParamArray IEnumerables() As IEnumerable(Of Object)) As List(Of Object())
Return GetCombinationsFromIEnumerables(chain:=New Object() {}, IEnumerables:=IEnumerables.AsEnumerable)
End Function
And the equivalent in C#:
public static List<object[]> GetCombinationsFromIEnumerables(ref object[] chain, ref IEnumerable<IEnumerable<object>> IEnumerables)
{
List<object[]> Combinations = new List<object[]>();
if (IEnumerables.Any) {
foreach ( v in IEnumerables.First) {
Combinations.AddRange(GetCombinationsFromIEnumerables(chain.Concat(new object[] { v }).ToArray, IEnumerables.Skip(1)).ToArray);
}
} else {
Combinations.Add(chain);
}
return Combinations;
}
public static List<object[]> GetCombinationsFromIEnumerables(params IEnumerable<object>[] IEnumerables)
{
return GetCombinationsFromIEnumerables(chain = new object[], IEnumerables = IEnumerables.AsEnumerable);
}
Easy to use:
Dim list1 = New String() {"hello", "bonjour", "hallo", "hola"}
Dim list2 = New String() {"Erwin", "Larry", "Bill"}
Dim list3 = New String() {"!", ".."}
Dim result = MyLib.GetCombinationsFromIEnumerables(list1, list2, list3)
For Each r In result
Debug.Print(String.Join(" "c, r))
Next
or in C#:
object list1 = new string[] {"hello","bonjour","hallo","hola"};
object list2 = new string[] {"Erwin", "Larry", "Bill"};
object list3 = new string[] {"!",".."};
object result = MyLib.GetCombinationsFromIEnumerables(list1, list2, list3);
foreach (r in result) {
Debug.Print(string.Join(' ', r));
}
Here is a version which uses very little code, and is entirely declarative
public static IEnumerable<IEnumerable<T>> GetPermutations<T>(IEnumerable<T> collection) where T : IComparable
{
if (!collection.Any())
{
return new List<IEnumerable<T>>() {Enumerable.Empty<T>() };
}
var sequence = collection.OrderBy(s => s).ToArray();
return sequence.SelectMany(s => GetPermutations(sequence.Where(s2 => !s2.Equals(s))).Select(sq => (new T[] {s}).Concat(sq)));
}
class Program
{
static void Main(string[] args)
{
var listofInts = new List<List<int>>(3);
listofInts.Add(new List<int>{1, 2, 3});
listofInts.Add(new List<int> { 4,5,6 });
listofInts.Add(new List<int> { 7,8,9,10 });
var temp = CrossJoinLists(listofInts);
foreach (var l in temp)
{
foreach (var i in l)
Console.Write(i + ",");
Console.WriteLine();
}
}
private static IEnumerable<List<T>> CrossJoinLists<T>(IEnumerable<List<T>> listofObjects)
{
var result = from obj in listofObjects.First()
select new List<T> {obj};
for (var i = 1; i < listofObjects.Count(); i++)
{
var iLocal = i;
result = from obj in result
from obj2 in listofObjects.ElementAt(iLocal)
select new List<T>(obj){ obj2 };
}
return result;
}
}
Here's a non-recursive, non-Linq solution. I can't help feeling like I could have less looping and calculate the positions with division and modulo, but can't quite wrap my head around that.
static void Main(string[] args)
{
//build test list
List<string[]> myList = new List<string[]>();
myList.Add(new string[0]);
myList.Add(new string[0]);
myList.Add(new string[0]);
myList[0] = new string[] { "1", "2", "3"};
myList[1] = new string[] { "4", "5" };
myList[2] = new string[] { "7", "8", "9" };
object[][] xProds = GetProducts(myList.ToArray());
foreach(object[] os in xProds)
{
foreach(object o in os)
{
Console.Write(o.ToString() + " ");
}
Console.WriteLine();
}
Console.ReadKey();
}
static object[][] GetProducts(object[][] jaggedArray){
int numLists = jaggedArray.Length;
int nProducts = 1;
foreach (object[] oArray in jaggedArray)
{
nProducts *= oArray.Length;
}
object[][] productAry = new object[nProducts][];//holds the results
int[] listIdxArray = new int[numLists];
listIdxArray.Initialize();
int listPtr = 0;//point to current list
for(int rowcounter = 0; rowcounter < nProducts; rowcounter++)
{
//create a result row
object[] prodRow = new object[numLists];
//get values for each column
for(int i=0;i<numLists;i++)
{
prodRow[i] = jaggedArray[i][listIdxArray[i]];
}
productAry[rowcounter] = prodRow;
//move the list pointer
//possible states
// 1) in a list, has room to move down
// 2) at bottom of list, can move to next list
// 3) at bottom of list, no more lists left
//in a list, can move down
if (listIdxArray[listPtr] < (jaggedArray[listPtr].Length - 1))
{
listIdxArray[listPtr]++;
}
else
{
//can move to next column?
//move the pointer over until we find a list, or run out of room
while (listPtr < numLists && listIdxArray[listPtr] >= (jaggedArray[listPtr].Length - 1))
{
listPtr++;
}
if (listPtr < listIdxArray.Length && listIdxArray[listPtr] < (jaggedArray[listPtr].Length - 1))
{
//zero out the previous stuff
for (int k = 0; k < listPtr; k++)
{
listIdxArray[k] = 0;
}
listIdxArray[listPtr]++;
listPtr = 0;
}
}
}
return productAry;
}
One of the problems I encountred when I was doing this for a very large amount of codes was that with the example brian was given I actually run out of memory. To solve this I used following code.
static void foo(string s, List<Array> x, int a)
{
if (a == x.Count)
{
// output here
Console.WriteLine(s);
}
else
{
foreach (object y in x[a])
{
foo(s + y.ToString(), x, a + 1);
}
}
}
static void Main(string[] args)
{
List<Array> a = new List<Array>();
a.Add(new string[0]);
a.Add(new string[0]);
a.Add(new string[0]);
a[0] = new string[] { "T", "Z" };
a[1] = new string[] { "N", "Z" };
a[2] = new string[] { "3", "2", "Z" };
foo("", a, 0);
Console.Read();
}
private static void GetP(List<List<string>> conditions, List<List<string>> combinations, List<string> conditionCombo, List<string> previousT, int selectCnt)
{
for (int i = 0; i < conditions.Count(); i++)
{
List<string> oneField = conditions[i];
for (int k = 0; k < oneField.Count(); k++)
{
List<string> t = new List<string>(conditionCombo);
t.AddRange(previousT);
t.Add(oneField[k]);
if (selectCnt == t.Count )
{
combinations.Add(t);
continue;
}
GetP(conditions.GetRange(i + 1, conditions.Count - 1 - i), combinations, conditionCombo, t, selectCnt);
}
}
}
List<List<string>> a = new List<List<string>>();
a.Add(new List<string> { "1", "5", "3", "9" });
a.Add(new List<string> { "2", "3" });
a.Add(new List<string> { "93" });
List<List<string>> result = new List<List<string>>();
GetP(a, result, new List<string>(), new List<string>(), a.Count);
Another recursive function.