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What are the lesser known but useful data structures?
...s are painfully expensive, given that a pointer is generally longer than a char, which is a shame. They're only suitable for certain data-sets.
– Joe
Jan 29 '10 at 12:06
18
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How do I find the .NET version?
...ersion,Release -EA 0 |
where { $_.PSChildName -match '^(?!S)\p{L}'} | select PSChildName, Version, Release
The last command (8) will give you all versions, including .NET 4.5.
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LINQ's Distinct() on a particular property
...
(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
{
HashSet<TKey> seenKeys = new HashSet<TKey>();
foreach (TSource element in source)
{
if (seenKeys.Add(keySelector(element)))
{
yield return element;
}
...
Select rows of a matrix that meet a condition
...20, ncol = 4)
colnames(m) <- letters[1:4]
The following command will select the first row of the matrix above.
subset(m, m[,4] == 16)
And this will select the last three.
subset(m, m[,4] > 17)
The result will be a matrix in both cases.
If you want to use column names to select columns...
Fluent and Query Expression — Is there any benefit(s) of one over other?
...me in fullNames
from name in fullName.Split()
orderby fullName, name
select name + " came from " + fullName;
Now compare this to the same thing in method syntax:
var query = fullNames
.SelectMany (fName => fName.Split().Select (name => new { name, fName } ))
.OrderBy (x => x.fN...
Invoke a callback at the end of a transition
...
You want to listen for the "end" event of the transition.
// d3 v5
d3.select("#myid").transition().style("opacity","0").on("end", myCallback);
// old way
d3.select("#myid").transition().style("opacity","0").each("end", myCallback);
This demo uses the "end" event to chain many transitions in...
What's the difference(s) between .ToList(), .AsEnumerable(), AsQueryable()?
...y we would typically write something like
var query = context.Observations.Select(o => o.Id)
.AsEnumerable().Select(x => MySuperSmartMethod(x))
ToList – which converts an IEnumerable<T> to a List<T> – is often used for this purpose as well. The advantage of...
Use 'class' or 'typename' for template parameters? [duplicate]
...s expected T will always be a class, with "typename" if other types (int, char* whatever) may be expected. Consider it a usage hint.
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Replace selector images programmatically
I have an ImageView that has a drawable image resource set to a selector. How do I programmatically access the selector and change the images of the highlighted and non-highlighted state?
...
SELECT * WHERE NOT EXISTS
...uming these tables should be joined on employeeID, use the following:
SELECT *
FROM employees e
WHERE NOT EXISTS
(
SELECT null
FROM eotm_dyn d
WHERE d.employeeID = e.id
)
You can join these tables with a LEFT JOIN keyword and filter out the...