Develop Reference

Is It possible to find out what are the common part in String List

I was working on finding out the Common string part in the String list. If we take a sample data set
private readonly List<string> Xpath = new List<string>()
{
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(1)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(2)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(3)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(4)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(5)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(6)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(7)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(8)>H2:nth-of-type(1)",
"BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>SECTION:nth-of-type(9)>H2:nth-of-type(1)"
};
From this, I want to find out to which children these are similar. data is an Xpath list.
Programmatically I should be able to tell
Expected output:
BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV
In order to get this What I did was like this. I separate each item by > and then create a list of items for each dataset originally.
Then using this find out what are the unique items
private IEnumerable<T> GetCommonItems<T>(IEnumerable<T>[] lists)
{
HashSet<T> hs = new HashSet<T>(lists.First());
for (int i = 1; i < lists.Length; i++)
{
hs.IntersectWith(lists[i]);
}
return hs;
}
Able to find out the unique values and create a dataset again. But what happened is if this contains Ex:- Div in two places and it also in every originally dataset even then this method will pick up only one Div.
From then I would get something like this:
BODY>MAIN:nth-of-type(1)>DIV>SECTION
But I need this
BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-
type(3)>DIV>ARTICLE>DIV>DIV>DIV

Disclaimer: This is not the most performant solution but it works :)
Let's start with splitting the first path by > character
Do the same with all the paths
char separator = '>';
IEnumerable<string> firstPathChunks = Xpath[0].Split(separator);
var chunks = Xpath.Select(path => path.Split(separator).ToList()).ToArray();
Iterate through the firstPathChunks
Iterate through the chunks
if there is a match then remove the first element
if all first element is removed then append the matching prefix to sb
void Process(StringBuilder sb)
{
foreach (var pathChunk in firstPathChunks)
{
foreach (var chunk in chunks)
{
if (chunk[0] != pathChunk)
{
return;
}
chunk.RemoveAt(0);
}
sb.Append(pathChunk);
sb.Append(separator);
}
}
Sample usage
var sb = new StringBuilder();
Process(sb);
Console.WriteLine(sb.ToString());
Output
BODY>MAIN:nth-of-type(1)>DIV>SECTION>DIV>SECTION>DIV>DIV:nth-of-type(1)>DIV>DIV:nth-of-type(3)>DIV>ARTICLE>DIV>DIV>DIV>

Parsing the string by the seperator > is a good idea. Instead of then creating a list of unique items you should create a list of all items contained in the string which would result in
{
"BODY",
"MAIN:nth-of-type(1)",
"DIV",
"SECTTION",
"DIV",
...
}
for the first entry of your XPath list.
This way you create a List<List<string>> containing every element of each entry of your XPath list. You then can compare all first elements of the inner lists. If they are equal save that elements value to you output and proceed with all second elements and so on until you find an element that is not equal in all outer lists.
Edit:
After seperating your list by the > seperator this could look something like this:
List<List<string>> XPathElementsLists;
List<string> resultElements = new List<string>();
string result;
XPathElementsLists = ParseElementsFormXPath(XPath);
for (int i = 0; i < XPathElementsLists[0].Count; i++)
{
bool isEqual = true;
string compareElemment = XPathElementsLists[0][i];
foreach (List<string> element in XPathElementsLists)
{
if (!String.Equals(compareElemment, element))
{
isEqual = false;
break;
}
}
if (!isEqual)
{
break;
}
resultElements.Add(compareElemment);
}
result = String.Join(">", resultElements.ToArray());

How do i get the value of first index in a returned List of array

I am using C# windows form
I have a List of arrays from a function in a class and I called the function into the form
the function returned a List of arrays, how do i get the value of the arrays?
Here is my List of array code
public List<string[]> getAccounts()
{
List<string[]> account = new List<string[]>();
while (*condition*)
{
string[] users = new string[2];
users[0] = user["firstname"].ToString();
users[1] = user["lastname"].ToString();
account.Add(users);
}
return account;
}
and when i call the function I want to show all the firstname into a listbox as well as the last name into another listbox
for (int i = 1; i <= acc.getAccounts().Count; i++)
{
listBoxFirstname.Items.Add(*all the first name from the list*);
}

Use a lambda expression to iterate through the list and select the first name
account.ForEach(s => listBoxFirstname.Items.Add(s[0]));

Without a lambda expression:
List<string[]> accounts = acc.getAccounts()
for (int i = 1; i < accounts ; i++)
{
listBoxFirstname.Items.Add(account[i][0]);
listBoxLastname.Items.Add(account[i][1]);
}

This should do the job:
List<string> firstNames = account.Select(item => item[0]).ToList();

I think will be better to use SelectMany.
listBoxFirstname.Items.AddRange(acc.getAccounts().SelectMany(item=>item[0]))
AddRange
SelectMany
EDIT:
Sorry, i'm blind, you can do it without Select many - you can just use Select
listBoxFirstname.Items.AddRange(acc.getAccounts().Select(item=>item[0]))

take one value from multiple loops

I have a list of arrays, of which i want to take one value from each array and build up a JSON structure. Currently for every managedstrategy the currency is always the last value in the loop. How can i take the 1st, then 2nd value etc while looping the names?
List<managedstrategy> Records = new List<managedstrategy>();
int idcnt = 0;
foreach (var name in results[0])
{
managedstrategy ms = new managedstrategy();
ms.Id = idcnt++;
ms.Name = name.ToString();
foreach (var currency in results[1]) {
ms.Currency = currency.ToString();
}
Records.Add(ms);
}
var Items = new
{
total = results.Count(),
Records
};
return Json(Items, JsonRequestBehavior.AllowGet);
JSON structure is {Records:[{name: blah, currency: gbp}]}

Assuming that I understand the problem correctly, you may want to look into the Zip method provided by Linq. It's used to "zip" together two different lists, similar to how a zipper works.
A related question can be found here.

Currently, you are nesting the second loop in the first, resulting in it always returning the last currency, you have to put it all in one big for-loop for it to do what you want:
for (int i = 0; i < someNumber; i++)
{
// some code
ms.Name = results[0][i].ToString();
ms.Currency = results[1][i].ToString();
}

how to dissect string values

How can I dissect or retrieve string values?
Here's the sample code that I'm working on now:
private void SplitStrings()
{
List<string> listvalues = new List<string>();
listvalues = (List<string>)Session["mylist"];
string[] strvalues = listvalues.ToArray();
for (int x = 0; x < strvalues.Length; x++)
{
}
}
Now that I'am able to retrieve list values in my session. How can I separately get the values of each list using foreach or for statement?
What I want to happen is to programmatically split the values of the strings depending on how many is in the list.

If you have a list of string values, you can do the following:
private void SplitStrings()
{
List<string> listValues = (List<string>) Session["mylist"];
// always check session values for null
if(listValues != null)
{
// go through each list item
foreach(string stringElement in listValues)
{
// do something with variable 'stringElement'
System.Console.WriteLine(stringElement);
}
}
}
Note that I test the result of casting the session and that I don't create a new list first-off, which is not necessary. Also note that I don't convert to an array, simply because looping a list is actually easier, or just as easy, as looping an array.
Note that you named your method SplitStrings, but we're not splitting anything. Did you mean to split something like "one;two;three;four" in a four-element list, based on the separator character?

I'm not sure what you're trying to obtain in this code, I don't know why you're converting your List to an Array.
You can loop through your listValues collection with a foreach block:
foreach(string value in listValues)
{
//do something with value, I.e.
Response.Write(value);
}

I don't know what's in the strings but you can start by simplifying. There is no point allocating a new List if you're going to overwrite it immediately.
private void SplitStrings()
{
List<string> list = (List<string>)Session["mylist"];
foreach(string value in list)
{
}
}

List listvalues = (List)Session["mylist"];
foreach (string s in listvalues)
{
//do what you want with s here
}

How to do a search from a list with non-prefix keywords

I am programming a program to search the name from the list and I need to find them even if the keyword is not in front of the names (that's what I mean non-prefix)
e.g. if I my list is the music instruments and I type "guit" to the search textbox.
It should find the names "Guitar, Guitarrón, Acoustic Guitar, Bass Guitar, ..."
or something like this Longdo Dictionary's search suggestion.
here is my simple and stupid algorithm (that's all I can do)
const int SEARCHROWLIMIT = 30;
private string[] DoSearch(string Input, string[] ListToSearch)
{
List<string> FoundNames = new List<string>();
int max = 0;
bool over = false;
for (int k = 0; !over; k++)
{
foreach (string item in ListToSearch)
{
max = (max > item.Length) ? max : item.Length;
if (k > item.Length) continue;
if (k >= max) { over = true; break; }
if (!Input.Equals("Search")
&& item.Substring(k, item.Length - k).StartsWith(Input, StringComparison.OrdinalIgnoreCase))
{
bool exist = false;
int i = 0;
while (!exist && i < FoundNames.Count)
{
if (item.Equals(FoundNames[i]))
{
exist = true;
break;
}
i++;
}
if (!exist && FoundNames.Count < SEARCHROWLIMIT)
FoundNames.Add(item);
else if (FoundNames.Count >= SEARCHROWLIMIT) over = true;
}
}
}
return FoundNames.ToArray();
}
I think this algorithm is too slow for a large number of names and after several trial-and-error, I decided to add SEARCHROWLIMIT to breaks the operation
And I also think there're some readymade methods that can do that.
And another problem is I need to search music instruments by a category like strings, percussions, ... and by the country of origins. So I need to search them with filter by type and country.
How can I achieve this?

Using LINQ you could write code like this:
var resultSet = products
// filter products by category
.Where(product => product.Category == "strings")
// filter products by origin
.Where(product => product.Origin == "italy")
// filter products whose name contains a word starting with "guit"
.Where(product => (" " + product.Name).Contains(" guit"))
// limit the result set to the first 30 matching products
.Take(30);
If your sets of products is reasonably small, you can use LINQ-to-Objects. Otherwise you should use a database and have a look at LINQ-to-SQL.

One word. Database!
Seriously, if you want to do all these different searches, consider placing your data into a database with a schema that simplifies the categorization issues you are having. Sql Server Express now supports full text search which would be very useful for the kind of search you are trying to perform.
There's a nice blog post here about using FTS with Linq-to-Sql.

static List<string> GetItemsWithWordsStartingWithSubstring(List<string> list, string substring)
{
var query = from str in list
from item in str.Split(' ')
where item.StartsWith(substring, StringComparison.InvariantCultureIgnoreCase)
select str;
return query.ToList();
}
I hope I have read your intiial question properly. This function will return any item from the list that contains a word starting with your substring. More punctuation could be added to the split parameters. Given a list with the following contents:
"abcdef","defabc","def abc","xyz"
A search on "abc" will find "abcdef" and "def abc", but not "defabc".