Finding maximum and minimum Value column wise in datatable

Farhan Shariff

I have two tables I want to compare them using Par Name column(here rows are compare with columns of table5) and find lowest and highest values

table 1

Par Name	SKIP	Lowest value	Highest Value
D_Id	0
Split	0
Val_2	0
Val_1	0
Val_4	0

table5

D_ID	Split	Val_1	Val_2	Val_4
N_01	Ret	-0.13672	-0.56202	-0.4211
N_92	Ret	-0.13767	-0.13911	-0.56752
N_03	Stress	-0.13711	-0.42072	-0.41932
N_98	Stress	-0.6132	-0.41979	-0.42025
N_56	Stress	-0.42026	-0.41955	-0.1367

for (int q = 2; q < table1.Rows.Count; q++)
{

string colVal = table1.Rows[q]["Par Name"].ToString();
if(table5.Columns.Contains(colVal))
{

// Error : Specified cast is not valid
table1.Rows[q]["Lowest value"] = table5.AsEnumerable().Min(r => r.Field(colVal));
table1.Rows[q]["Highest Value"] = table5.AsEnumerable().Max(r => r.Field(colVal));
}
}

output table

Par Name	SKIP	Lowest value	Highest Value
D_Id	0
Split	0
Val_2	0	-0.56202	-0.13911
Val_1	0	-0.6132	-0.13672
Val_4	0	-0.56752	-0.1367

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes12y ago
Accepted answer
Assuming the columns are of type double and not string, then try instead:

table1.Rows[q]["Lowest value"] = table5.Rows.Cast().Min(r => r.Field(colVal));
table1.Rows[q]["Highest Value"] = table5.Rows.Cast().Max(r => r.Field(colVal));

If they're strings, then change:

r.Field(colVal)

to:

double.Parse( r.Field(colVal))
Vulpes12y ago
I don't think there's a more effective way to do it but the following formulation is arguably more elegant:

foreach(DataRow row in table1.Rows.Cast().Skip(2))
{
string colVal = row["Par Name"].ToString();
if (table5.Columns.Contains(colVal))
{
r["Lowest value"] = table5.Rows.Cast().Min(r => double.Parse(r.Field(colVal)));
r["Highest value"] = table5.Rows.Cast().Max(r => double.Parse(r.Field(colVal)));
}
}
Farhan Shariff12y ago
here I am using

for (int q = 2; q < table1.Rows.Count; q++)
{

}

since first and second column are D_Id and Split is there a much effective way to do that ?
Farhan Shariff12y ago
double.Parse( r.Field(colVal)) works perfect Thanx Vuples :)