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linq query to return distinct field values from a list of objects
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objList.Select(o=>o.typeId).Distinct()
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“A lambda expression with a statement body cannot be converted to an expression tree”
...SQL to be executed against the database.
Try this
Arr[] myArray = objects.Select(o => new Obj() {
Var1 = o.someVar,
Var2 = o.var2
}).ToArray();
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How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?
...(1) (in relation to the upper bound). Maybe the longest english word is 50 characters?
8 Answers
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What columns generally make good indexes?
...earching the results speedily from tables. So it is most important step to select which columns to be indexed. There are two major places where we can consider indexing: columns referenced in the WHERE clause and columns used in JOIN clauses. In short, such columns should be indexed against which yo...
How to force LINQ Sum() to return 0 while source collection is empty
...word
&& l.Property.PropertyId == PropertyId)
.Select(l => l.Amount)
.DefaultIfEmpty(0)
.Sum();
This way, your query will only select the Amount field. If the collection is empty, it will return one element with the value of 0 and then the sum will ...
Fastest way(s) to move the cursor on a terminal command line?
...the previous line, you can use quick substitution: ^--option25^--newoption
Character search. This was mentioned by Pax, and can be done in regular emacs-mode with Ctrl+] for forward search, and Ctrl+Alt+] for backward search.
I recommend the second option. Ctrl+r is really handy and fast, no mucki...
Why can't radio buttons be “readonly”?
...ton by disabling only the un-checked radio buttons. It keeps the user from selecting a different value, and the checked value will always post on submit.
Using jQuery to make readonly:
$(':radio:not(:checked)').attr('disabled', true);
This approach also worked for making a select list readonly, ...
XPath - Selecting elements that equal a value
In Xpath, I am wanting to select elements that equal a specific value.
2 Answers
2
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How to make a variadic macro (variable number of arguments)
...void)0) //strip out PRINT instructions from code
#endif
void print(const char *fmt, ...) {
va_list args;
va_start(args, fmt);
vsprintf(str, fmt, args);
va_end(args);
printf("%s\n", str);
}
int main() {
PRINT("[%s %d, %d] Hello World", "March", 26, 2009);
retur...
Comparing date ranges
... range_start, here's some simple SQL to retrieve all the matching rows:
SELECT *
FROM periods
WHERE NOT (range_start > @check_period_end
OR range_end < @check_period_start)
Note the NOT in there. Since the two simple rules finds all the non-matching rows, a simple NOT will reve...