Is there is a LINQ expression equivalent to below code?
int noOfColumns = 10;
for (int i = 2; i <= noOfColumns+1; i++)
{
sql.AppendFormat(" [{0}{1}] [varchar]({2}),", "commodity", columnLength);
}
4 Answers
Enumerable.Range(2, noOfColumns+1)
.ToList()
.ForEach(i =>
sql.AppendFormat(" [{0}{1}] [varchar]({2}),", "commodity" columnLength));
But I don't think it looks better :-).
3 Comments
Rawling
I've removed my
-1 because I'm pretty sure you're joking :)
EgorBo
It is just an answer for the question :-) I hope it will tell author that it's not necessary to use LINQ everywhere
huMpty duMpty
@Nagg: I am not sure how this part doesn't comes up with any errors
"commodity" columnLengthFor what it's worth, the (compiling) Linq replacement would be:
IEnumerable<string> cols = Enumerable.Range(2, noOfColumns +1)
.Select(i => string.Format(" [{0}] [varchar]({1})", "commodity", columnLength));
string sql = string.Join(",", cols);
But i must admit that i have no idea what you're doing.
5 Comments
Rawling
TIL that
String.Join uses a StringBuilder behind the scenes.
Tim Schmelter
@Rawling: Yes, you're right. Removed the "without
StringBuilder".Rawling
That wasn't a criticism, I'd just never thought about it and thought
Join (at least the array version) would allocate space for the whole thing and then fill it.Tim Schmelter
@Rawling: I've noticed it recently. But the
string.Join(string[]) overload uses a very efficient copy method memcpyimpl instead of a StringBuilder.
gee'K'iran
@TimSchmelter:I am just trying to generate dynamic sql to create a table from code behind. The number of columns will be changing at runtime (could be 1000 some times). Being novice to LINQ i thought it may add value. Thanks all for your time.
The parameters of Enumerable.Range are start and count. This means that it does not directly replace for loops.
for(var i = 5; i < 8; ++i) will produce the numbers from 5 to 7.
Enumerable.Range(5, 8) will produce the numbers from 5 to 12 (5+8-1).
To get the desired effect, Enumerable.Range(start, end - start) would need to be used.
Comments
Try This,
Enumerable.Range(2, noOfColumns).ToList().ForEach(r => { sql.AppendFormat(" [{0}{1}] [varchar]({2}),", "commodity" columnLength); });
4 Comments
Rawling
You're right, taking off the
+1 fixes a range error, doesn't it? Please accept my apologies. My downvote's locked in, but if you edit your answer (you could put some linebreaks in!) then I can remove it.huMpty duMpty
@Swani: Seems this doesn't compile !!
Prasad Kanaparthi
@huMptyduMpty, The question itself not compile ('[{0}{1}] [varchar]({2}),", "commodity" columnLength); '), if you ignore that part.. rest is complied code :).
huMpty duMpty
@Swani: So it mean it is fare to put something which not work as an answer?
linq?