C# Compare 2 strings, sorting, put into array

Question

hi im formulating my question now better.

in the foreach command i get for temp(save variable) values in an array. The values that i save in temp are from the datagridview cells.

in the next step, in the for command, i want to compare 2 strings, the string and the next string, if the fist string is bigger than the second, i want to change their positions. But there is the problem, they dont change positions they even get an empty value, and i cant understand why they get an empty value.

Im thinking that they get an empty value because of the foreach command, the index [i] just stays the same, but if i would put in i = i+1, the command would be out of bound.

Thank you

senc. NIko

foreach (DataGridViewRow row in dataGridView1.Rows)     
{
    if (row.Cells[i].Value == null)
    {
        //MessageBox.Show("This row is empty");
        break;
    }
    if (row.Cells[i].Value != null)
    {
        temp = row.Cells[i].Value.ToString();
        UnsortArray[i] = temp;
        i = i + 1;

    }
}

for (int a = 0; a < MaxZeilen; a++)
{
    if (i < MaxZeilen)
    {
        *if (String.Compare(UnsortArray[a], UnsortArray[a + 1]) > 0) 
        {
            UnsortArray[a] = temp;
            UnsortArray[a + 1] = temp2;
            temp = UnsortArray[a + 1];
            temp2 = UnsortArray[a];
        }*
    }
}

for (int i = 0; i < MaxZeilen; i++)
{
    UnsortArray[i] = SortArray[i];
    MessageBox.Show(UnsortArray[i]);
}

Do you want to sort all strings or just swap strings near each other? Your code doesn't sort all strings. {"22", "33", "11"} will become {"22", "11", "33"} — Dmitrii Dovgopolyi
– Dmitrii Dovgopolyi, Commented Sep 24, 2012 at 13:12
are you sure, that UnsortArray contains right strings after foreach code? — Dmitrii Dovgopolyi
– Dmitrii Dovgopolyi, Commented Sep 24, 2012 at 13:14
yes it was mentioned to sort the strings. but not with numbers, with names. like {"Pepsi" "Cola" "Fanta" "Orangejuice"} should become (alphabetic) {"Cola" "Fanta" "Orangejuice" "Pepsi"}. My mentor said it would work with compare, but im not sure.. — Niko
– Niko, Commented Sep 24, 2012 at 13:15
Please read some articles about sorting algorithms en.wikipedia.org/wiki/Sorting_algorithm — Dmitrii Dovgopolyi
– Dmitrii Dovgopolyi, Commented Sep 24, 2012 at 13:17
And in your foreach loop you read 1 value from 1 row and each time it is new column. Is it ok? — Dmitrii Dovgopolyi
– Dmitrii Dovgopolyi, Commented Sep 24, 2012 at 13:25

lc. · Accepted Answer · 2012-09-24 12:51:18Z

1

You're backwards, assigning the array to your temp variables before assigning the temp variables:

UnsortArray[a] = temp;
UnsortArray[a + 1] = temp2;
temp = UnsortArray[a + 1];
temp2 = UnsortArray[a];

Try:

temp = UnsortArray[a + 1];
temp2 = UnsortArray[a];
UnsortArray[a] = temp;
UnsortArray[a + 1] = temp2;

And you've done it again here UnsortArray[i] = SortArray[i];. I think you mean SortArray[i] = UnsortArray[i];

edited Sep 24, 2012 at 12:51

answered Sep 24, 2012 at 12:46

lc.

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2 Comments

Niko Over a year ago

unfortunetlly it doesnt works, changes nothing -.- BUT THANK YOU

Niko Over a year ago

ok i understand now whats going on, thank you for your help. but the problem still exists, as you can see i created a MessageBox for showing the values, and all boxes are empty. so sth is wrong, im searching further!

m4ngl3r · Accepted Answer · 2012-09-24 13:04:42Z

1

    temp = UnsortArray[a + 1];    

    UnsortArray[a + 1] = UnsortArray[a];

    UnsortArray[a] = temp;

instead of

          UnsortArray[a] = temp;

          UnsortArray[a + 1] = temp2;

          temp = UnsortArray[a + 1];

          temp2 = UnsortArray[a];

answered Sep 24, 2012 at 13:04

m4ngl3r

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Comments

Olivier Kaisin · Accepted Answer · 2012-09-24 13:10:56Z

1

Why using an array and not a List ?

This page tells about sorting lists.

answered Sep 24, 2012 at 13:10

Olivier Kaisin

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Comments

M Akin · Accepted Answer · 2012-09-24 13:23:23Z

1

Here is some improvements to your code. You had an error at the top that could cause a infinite loop and just use the Array.Sort method. If you want it to sort differently, add an IComparable interface.

foreach (DataGridViewRow row in dataGridView1.Rows)     
{
     if (row.Cells[i].Value == null)
     {
          //MessageBox.Show("This row is empty");
          i++;
          break;
     }
     else (row.Cells[i].Value != null)
     {
          UnsortArray[i] = row.Cells[i].Value.ToString();
          i++;
     }
}  

Array.Sort(UnsortArray);
SortArray = UnsortArray;

answered Sep 24, 2012 at 13:23

M Akin

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3 Comments

Niko Over a year ago

i dont know the sort method of array.sort. as mentioned i need to create an bubblesorting namesort programm.

Marc Gravell Over a year ago

Completely unrelated to this answer, but just wanted to message you: re your edit here - no, that is incorrect: you can have as many using statements as you want, with a single set of braces. The code compiles perfectly "as is"

M Akin Over a year ago

Thanks Marc. I took your code and compiled it, and it does compile. Thanks for the info. I also found another post that explains that in more detail. I couldn't find any info about this on the Microsoft site. My initial mistake might have been putting a semicolon after the using statements, and that would not compile.

Dmitrii Dovgopolyi · Accepted Answer · 2012-09-24 13:44:59Z

1

    List<String> itemList = new List<string>();
    foreach (DataGridViewRow row in dataGridView1.Rows)
    {
        if (row.Cells[0].Value = null)
        {
            itemList.Add(row.Cells[0].Value.ToString());
        }
    }

    itemList.Sort();
    string[] SortedArray = itemList.ToArray();

    for (int j = 0; j < SortedArray.Length; j++)
    {
        MessageBox.Show(SortedArray[j]);
    }

and if this code doesn't work, than add

foreach(string item in itemList)
{
    MessageBox.Show(item);
}

after first foreach loop and check the values

answered Sep 24, 2012 at 13:44

Dmitrii Dovgopolyi

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1 Comment

Niko Over a year ago

if (row.Cells[0].Value == null) ---> again null exception problem on itemlist.add code

Ankit · Accepted Answer · 2012-09-24 13:56:53Z

1

Replace it with the following code block

int i= 0;
foreach (DataGridViewRow row in dataGridView1.Rows)     
{
    if (row != null)
    {
        temp = row.ToString();
        UnsortArray[i] = temp;
        i = i + 1;
    }
}


for (int a = 0; a < MaxZeilen; a++)
{
    if (String.Compare(UnsortArray[a], UnsortArray[a + 1]) > 0) 
    {
        temp = UnsortArray[a + 1];             
        UnsortArray[a + 1] = UnsortArray[a];
        UnsortArray[a] = temp;
    }
}
for (int i = 0; i < MaxZeilen; i++)
{
    MessageBox.Show(UnsortArray[i]);
}

edited Sep 24, 2012 at 13:56

answered Sep 24, 2012 at 13:02

Ankit

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10 Comments

Niko Over a year ago

i have tried this already, but the code doesnt change anything. THANK YOU FOR YOUR HELP

Ankit Over a year ago

did you notice that i have removed the outer if condition ?

Niko Over a year ago

yes i did. your explaination was usefull for me, i would give up an up but i dont have enough reputations -.- No it didnt helped, as already said :&

Ankit Over a year ago

are you setting the value of i above foreach loop ?

Ankit Over a year ago

this is the case when you are comparing values of different columns in a datagrid. if you are try to compare values of same columns and different row then you need a different construct.

|

m4ngl3r · Accepted Answer · 2012-09-25 07:15:22Z

1

int MaxArrayCount = 0; 
foreach(DataGridViewRow row in dataGridView1.Rows)    
{ 
MaxArrayCount += row.Cells.Count;
 }
 string[] UnsortArray= new string[MaxArrayCount];



int cnt = 0;
foreach (DataGridViewRow row in dataGridView1.Rows)
                {
                    for (int i = 0; i < row.Cells.Count; i++ )
                    {
                        if (row.Cells[i].Value != null)
                        {
                            temp = row.Cells[i].Value.ToString();

                            UnsortArray[cnt] = temp;

                            cnt++;
                        } 
                    }

                }



for (int b = 1; b < UnsortArray.Count; b++)
{    
  for (int a = 0; a < UnsortArray.Count - 1; a++)   
     {    

    if (String.Compare(UnsortArray[a], UnsortArray[a + 1]) > 0)
     {

      temp = UnsortArray[a + 1];

      UnsortArray[a + 1] = UnsortArray[a];

      UnsortArray[a] = temp;

    }    
  }    
}


for (int i = 0; i < MaxZeilen; i++)
{
MessageBox.Show(UnsortArray[i]);
}

edited Sep 25, 2012 at 7:15

answered Sep 25, 2012 at 6:21

m4ngl3r

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5 Comments

Niko Over a year ago

No doesnt work, i dont know how often do i say, i cant ++cnt, if i count cnt++ i get an out of bound, why does nobody understand this? THANK YOU

m4ngl3r Over a year ago

you cant get out of bound for cnt++ , until you have UnsortedArray[] limited in length , use: int MaxArrayCount = 0; foreach (DataGridViewRow row in dataGridView1.Rows) { MaxArrayCount += row.Cells.Count; } string[] UnsortArray= new string[MaxArrayCount];

Niko Over a year ago

ok you were right!!!! You solved it, THANK YOU VERY MUCH!!!!! Im now trying to get the values into another datagrid, little bit difficult but im optimistic =) THUMBS UP FOR HIM!!!!! ty

Niko Over a year ago

SURE, please do it, i have tried it yesterday, but i have too less reputations

m4ngl3r Over a year ago

i guess now you have enough repo to mark this as an answer. lol i'm being annoying i know, but still :D could you? D:D:

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