If I use break like the code below, then the loop within row won't iterate the rest if there is a match in the beginning, but what about the col loop?
Would it still iterate between 0 and 7? Is there a way to use break there as well?
for (int col = 0; col < 8; col ++)
for (int row = 0; row < 8; row ++)
if (check something)
{
//Then do this;
break;
}
One option is to use a condition flag. You could then either break in the outer loop as well, or just use it as an extra condition within the for loops:
bool keepGoing = true;
for (int col = 0; col < 8 && keepGoing; col++)
{
for (int row = 0; row < 8 && keepGoing; row++)
{
if (something)
{
// Do whatever
keepGoing = false;
}
}
}
In Java, you can specify a label to break to though. (I didn't see that this question was tagged Java as well as C#.)
outerLoop:
for (...)
{
for (...)
{
if (...)
{
break outerLoop;
}
}
}
EDIT: As noted in comments, in C#, you could use a label and goto:
for (...)
{
for (...)
{
if (...)
{
goto endOfLoop;
}
}
}
endOfLoop:
// Other code
I'd really recommend that you don't take either of these approaches though.
In both languages, it would usually be best to simply turn both loops into a single method - then you can just return from the method:
public void doSomethingToFirstOccurrence()
{
for (...)
{
for (...)
{
if (...)
{
return;
}
}
}
}
Yes, it is possible by using a break label:
package others;
public class A {
public static void main(String[] args) {
outer: for(int col = 0; col < 8; col ++)
{
for (int row = 0; row < 8; row ++)
{
if (col == 4)
{
System.out.println("hi");
break outer;
}
}
}
}
}
You can put logic like this:
boolean condition = false;
for (int col = 0; col < 8; col ++)
for (int row = 0; row < 8; row ++)
if (check something) {
// Then do this:
condition = true; // Break condition for outer loop
break;
}
}
if (condition)
break;
}
break only breaks the loop that is directly around it. You could use a flag to control the outer loop:
boolean continueOuterLoop = true;
for(int col = 0; continueOuterLoop && col < 8; col ++) {
for(int row = 0; row < 8; row ++) {
if(check something) {
//Then do this;
continueOuterLoop = false;
break;
}
}
}
It doesn't exit the col loop.
Instead, you can wrap all in a function and use return; to exit immediately from the loop
private Xy Loop( /* Parameters */)
for (int col = 0; col < 8; col ++)
for (int row = 0; row < 8; row ++)
if (check something) {
// Then do this;
return something; //Or just return;
}
}
}
}
nameHere:
for (yourForLoop) {
for (anotherLoop) {
if(condition) {
break nameHere;
}
}
}
One more alternative to the other answers is to set your counters to the maximum, to stop the loops.
for (int col = 0; col < 8; col ++)
for (int row = 0; row < 8; row ++)
if (check something)
{
// Use the col and row here.
// Now we go for a totally break of all loops.
// To stop the loops you can set that to the maximum
// of your loop test.
row = 8;
col = 8;
}
The advantage to that trick is that you do not add any additional checking code to the full loop and that makes it a lot faster.
In Java, you can use a break label.
outer:
for (int col = 0; col < 8; col ++)
for (int row = 0; row < 8; row ++)
if (check something)
{
break outer;
}
}
}
And, since nobody else has mentioned it yet, in C#, you can use goto label.
for (int col = 0; col < 8; col ++)
for (int row = 0; row < 8; row ++)
if (check something)
{
goto outside;
}
}
}
outside:
I think you should use a tag or a label, like "outerLoop". This works in Java:
outerLoop:
for (int col = 0; col < 8; col ++)
for (int row = 0; row < 8; row ++)
if (check something)
{
//Then do this;
break outerLoop;
}
There are a few ways to do this. One way is to set the max value of the variable in the outer loop.
int maxcol = 8;
for (int col = 0; col < maxcol; col++)
{
for (int row = 0; row < 8; row++)
{
if (check something)
{
Then do this;
// cause the outer loop to break:
col = maxcol;
// break the inner loop
break;
}
}
}
Set the col = 8 and then break to inner loop.
Loop1:
for (int col = 0; col < 8; col ++)
{
for (int row = 0; row < 8; row ++)
{
if (condition)
{
break Loop1;
}
}
}
This could do what you need.
We could use the concept of a flag variable:
flag = 1;
for (int col = 0; col < 8; col ++)
{
if (flag == 1)
{
for (int row = 0; row < 8; row ++)
{
if (flag == 1)
{
if (check something)
{
//Then do this;
flag = 0;
}
}
}
}
}
Related
How to get Cell index after comparing values, for example i have this
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
if (dataGridView1.Rows[i].Cells[value].Value.ToString() == radTextBox1.Text)
{
//If the value matches how to get the row index of that
}
}
This might do the job:
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
if (dataGridView1.Rows[i].Cells[0].Value.ToString() == radTextBox1.Text)
{
dataGridView1.CurrentCell = dataGridView1.Rows[i].Cells[0];
}
}
If you are wanting to find the value in any cell then you need to use a nested loop.
dataGridView1.ClearSelection();
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
for (int c = 0; c < dataGridView1.Columns.Count; c++)
{
if (dataGridView1.Rows[i].Cells[c].Value.ToString() == radtextBox1.Text)
{
dataGridView1.Rows[i].Selected = true;
}
}
}
This will move through each row while checking all the columns for a value and will hilight any row where a cell has that value. Note that this code is case sensitive so "City" <> "city" but that is easily fixed using .ToUpper or .ToLower as needed.
One other thing to add, this code also is based off a DGV that has AllowUserToAddRows set to false. If you need the edit row, you either need to -1 from the count in the rows loops or check to ensure that the current row is false for .IsNewRow.
You found the Row you're looking for.
It's i variable in your code.
var requiredRowIndex = -1;
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
if (dataGridView1.Rows[i].Cells[value].Value.ToString() == radTextBox1.Text)
{
requiredRowIndex = i;
break;
}
}
if (requiredRowIndex != -1)
{
// It was found.
}
else
{
// It was not found.
}
You dont show us what is the value? It's actualy index of Cell you're looking for.
I am creating an automatic seat assignment web app. I can assign a single person to a seat. How do I assign two people sitting side by side in the same column?
public bool[,] seatTwoPerson(bool[,] seatArray)
{
for (int row = 0; row <= 29; row++)
{
for (int col = 0; col <= 5; col++)
{
if (!seatArray[row, col])
{
seatArray[row, col] = true;
return seatArray;
}
}
}
You need to check both seats:
if (!seatArray[row, col] && !seatArray[row+1, col])
Then set both to true if you find a match:
seatArray[row, col] = true;
seatArray[row+1, col] = true;
Also you need to adjust your for loop so that row+1 doesn't go past the end:
for (int row = 0; row <= seatArray.GetUpperBound(0) - 1; row++)
Change you inner for
for (int col = 1; col <= 5; col++)
{
if (!seatArray[row, col] && !seatArray[row, col-1])
{
seatArray[row, col] = true;
seatArray[row, col-1] =true;
return seatArray;
}
}
I have DataTable and i need to clear all empty columns. So here is code example:
for (var i = 0; i < table.Columns.Count; i++)
{
if (table.Rows.Cast<DataRow>().All(r => string.IsNullOrWhiteSpace(r[i].ToStringOrNull())))
{
table.Columns.RemoveAt(i--);
}
}
Question : How can i get row Number in If-statement ?
Thanks.
If by "row number", you mean the index of a Row object in the Rows collection, then you can't get that directly from the Row object. You can, as suggested in Vlad's comment, use something like this instead:
for (var i = 0; i < table.Columns.Count; i++)
{
if (Enumerable.Range(0, table.Rows.Count).All(
j => string.IsNullOrWhiteSpace(tables.Rows[j][i].ToStringOrNull())))
{
table.Columns.RemoveAt(i--);
}
}
That said, it seems to me that it would be better to process the data such that you visit each row only once. This should at the very least improve data locality, and in some scenarios could significantly improve performance. E.g.:
bool[] keepColumn = new bool[table.Columns.Count];
for (int i = 0; i < table.Rows.Count; i++)
{
for (int j = 0; j < table.Columns.Count; j++)
{
if (!keepColumn[j] &&
!string.IsNullOrWhiteSpace(table.Columns[j].ToStringOrNull()))
{
keepColumn[j] = true;
}
}
}
for (int i = table.Columns.Count - 1; i >= 0; i--)
{
if (!keepColumn[i])
{
table.Columns.RemoveAt(i);
}
}
It's obviously a bit more verbose, but IMHO it would be worth it in this case, because it's processing the data in their natural organization (i.e. tables are naturally rows that have columns, as opposed to columns that have rows).
I am reading a csv file which has column names in first line and values in line >1. I need to get the position of the column name. The only way I can think of is to do either switch or ifs. I read it somewhere that in my case , it is faster (better) to do the ifs. However the file has many columns (~120). Just wondering if there is an alternative(s).
private static void Get_Position(string line, performance p)
{
string[] line_split = line.Split(',');
for (int i = 0; i < line_split.Length; i++)
{
if (line_split[i].Contains(#"(0)\% Processor Time"))
{
p.percore[0] = i;
}
else if (line_split[i].Contains(#"(1)\% Processor Time"))
{
p.percore[1] = i;
}
else if (line_split[i].Contains("Private Bytes"))
{}
else if (line_split[i].contains("DPC")
{
}
//on and on and on with else ifs
What is preventing you from using a loop?
for (int i = 0; i < line_split.Length; i++)
{
for(var j = 0; j < 120; j++)
{
if(line_split[i].Contains(#"(" + j + ")\% Processor Time"))
{
p.percore[j] = i;
}
}
...
To maintain the same functionality as if else if then you could use a break inside the conditional.
Edit: The edit now made it clear that there is no clear pattern to the string in contains. Still, if you are writing out 120 if/else if statements you should store what you will be looking for in some type of collection. For example, a List would work. Then access the index j of the collection in your loop:
...
var listOfSearchItems = new List<string>() { "Private Bytes", "DPC" };
for (int i = 0; i < line_split.Length; i++)
{
for(var j = 0; j < 120; j++)
{
if(line_split[i].Contains(listOfSearchItems[j])
{
p.percore[j] = i;
}
}
...
I have the following code that should loop through all the rows in my DataGridView, and write all their cell values to a text file.
However, it outputs all the rows, but only the first cell of each one, and not the other three cells.
string file_name = "C:\\test1.txt";
var objWriter = new System.IO.StreamWriter(file_name);
int count = dgv.Rows.Count;
for (int row = 0; row < count; row++)
{
objWriter.WriteLine(dgv.Rows[row].Cells[0].Value.ToString());
}
objWriter.Close();
for (int row = 0; row < count; row++)
{
int colCount = dgv.Rows[row].Cells.Count;
for ( int col = 0; col < colCount; col++)
{
objWriter.WriteLine(dgv.Rows[row].Cells[col].Value.ToString());
}
// record seperator could be written here.
}
Although, it would be cleaner if you used a foreach loop.
TextWriter sw = new StreamWriter(#"D:\\file11.txt");
int rowcount = dataGridViewX1.Rows.Count;
for (int i = 0; i < rowcount - 1; i++)
{
sw.WriteLine(dataGridViewX1.Rows[i].Cells[0].Value.ToString());
}
sw.Close();
MessageBox.Show("Text file was created." );