Lookback logic in a dataset

Joe

I have a dataset as below. I want to iterate through the dataset
comparing the value of the Code column to the value in the previous
row. If they are the same then I want to concatenate the value of the
Desc column in my current row to that of the value in the previous row.
If the value of Code is different to the value in the previous row then
I want to output the row to a dataset. I managed to achieve this
functionality but in a very messy way I'm sure there must be a more
elegant solution to what I have come up with.

Can anyone come up with a simple algorithm to solve this?

Input dataset

ItemNum Code Desc
1 A Apple
2 A Cider
3 A Scrumpy
4 B Strawberry

Resulting dataset
Code Desc
A Apple Cider Scrumpy
B Strawberry
Joe

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Nov 17 '05 #1

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1114

Ivan Wong

My example assumes that you are the data store in a table called "Table1"

string prevCode;
DataTable table = ds.Tables["Table1"];
DataRow row = table.Rows[0];
prevCode = (string)row["Code"];
for(int i = 1; i < table.Rows.Coun t; i++)
{
row = table.Rows[i];
if(row["Code"] == prevCode)
{
(table.Rows[i-1])["Desc"] = String.Concat(( table.Rows[i-1])["Desc"],
row["Desc"]);
table.Rows.Remo veAt(i);
i -= 1;
}
}

hope it helps,
Ivan Wong

"Joe" wrote:

I have a dataset as below. I want to iterate through the dataset
comparing the value of the Code column to the value in the previous
row. If they are the same then I want to concatenate the value of the
Desc column in my current row to that of the value in the previous row.
If the value of Code is different to the value in the previous row then
I want to output the row to a dataset. I managed to achieve this
functionality but in a very messy way I'm sure there must be a more
elegant solution to what I have come up with.

Can anyone come up with a simple algorithm to solve this?

Input dataset

ItemNum Code Desc
1 A Apple
2 A Cider
3 A Scrumpy
4 B Strawberry

Resulting dataset
Code Desc
A Apple Cider Scrumpy
B Strawberry
Joe

--
Sent via .NET Newsgroups
http://www.dotnetnewsgroups.com

Nov 17 '05 #2

Ivan Wong

just wanna make some correction for my post

"Ivan Wong" wrote:

My example assumes that you are the data store in a table called "Table1"

string prevCode;
DataTable table = ds.Tables["Table1"];
DataRow row = table.Rows[0];
prevCode = (string)row["Code"];
for(int i = 1; i < table.Rows.Coun t; i++)
{
row = table.Rows[i];
if(row["Code"] == prevCode)
{
(table.Rows[i-1])["Desc"] = String.Concat(( table.Rows[i-1])["Desc"],
row["Desc"]);
table.Rows.Remo veAt(i);
i -= 1;
} else
{
prevCode = row["Code"];
} }

hope it helps,
Ivan Wong

"Joe" wrote:
I have a dataset as below. I want to iterate through the dataset
comparing the value of the Code column to the value in the previous
row. If they are the same then I want to concatenate the value of the
Desc column in my current row to that of the value in the previous row.
If the value of Code is different to the value in the previous row then
I want to output the row to a dataset. I managed to achieve this
functionality but in a very messy way I'm sure there must be a more
elegant solution to what I have come up with.

Can anyone come up with a simple algorithm to solve this?

Input dataset

ItemNum Code Desc
1 A Apple
2 A Cider
3 A Scrumpy
4 B Strawberry

Resulting dataset
Code Desc
A Apple Cider Scrumpy
B Strawberry
Joe

--
Sent via .NET Newsgroups
http://www.dotnetnewsgroups.com

Nov 17 '05 #3

Ivan Wong

"Ivan Wong" wrote:

My example assumes that you are the data store in a table called "Table1"

string prevCode;
DataTable table = ds.Tables["Table1"];
DataRow row = table.Rows[0];
prevCode = (string)row["Code"];
for(int i = 1; i < table.Rows.Coun t; i++)
{
row = table.Rows[i];
if((string)row["Code"] == prevCode)
{
(table.Rows[i-1])["Desc"] = String.Concat(( table.Rows[i-1])["Desc"],
row["Desc"]);
table.Rows.Remo veAt(i);
i -= 1;
} else
{
prevCode = (string) row["Code"];
} }

hope it helps,
Ivan Wong

"Joe" wrote:
I have a dataset as below. I want to iterate through the dataset
comparing the value of the Code column to the value in the previous
row. If they are the same then I want to concatenate the value of the
Desc column in my current row to that of the value in the previous row.
If the value of Code is different to the value in the previous row then
I want to output the row to a dataset. I managed to achieve this
functionality but in a very messy way I'm sure there must be a more
elegant solution to what I have come up with.

Can anyone come up with a simple algorithm to solve this?

Input dataset

ItemNum Code Desc
1 A Apple
2 A Cider
3 A Scrumpy
4 B Strawberry

Resulting dataset
Code Desc
A Apple Cider Scrumpy
B Strawberry
Joe

--
Sent via .NET Newsgroups
http://www.dotnetnewsgroups.com

Nov 17 '05 #4

Joe

Thanks Ivan - this works very well and is three times less code than I
had previously! Thank you

Joe

--
Sent via .NET Newsgroups
http://www.dotnetnewsgroups.com

Nov 17 '05 #5

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