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Is it better to use Enumerable.Empty() as opposed to new List() to initialize an IEnumerable
...uld be noticeable impact.
Enumerable.Empty does not create an object per call thus putting less load on GC.
If the code is in low-throughput location, then it boils down to aesthetic considerations though.
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Select distinct values from a table field
...ant any ordering to be applied to a query, not even the default ordering, call order_by() with no parameters.
and distinct() in the note where it discusses issues with using distinct() with ordering.
To query your DB, you just have to call:
models.Shop.objects.order_by().values('city').distinct(...
STL or Qt containers?
... (see the std::string COW controversy). Some STL implementations are especially
bad.
provide hashes, which are not available unless you use TR1
The QTL has a different philosophy from the STL, which is well summarized by J. Blanchette: "Whereas STL's containers are optimized for raw speed, Qt's co...
How to create NS_OPTIONS-style bitmask enumerations in Swift?
...tains(.secondOption) {
print("multipleOptions has SecondOption")
}
let allOptions = MyOptions(rawValue: 7)
if allOptions.contains(.thirdOption) {
print("allOptions has ThirdOption")
}
Swift 2.0
In Swift 2.0, protocol extensions take care of most of the boilerplate for these, which are now...
Insert picture into Excel cell [closed]
... appear on hover over.
Microsoft Office 365 (2019) introduced new things called comments and renamed the old comments as "notes". Therefore in the steps above do New Note instead of Insert Comment. All other steps remain the same and the functionality still exists.
There is also a $20 product fo...
Is there a __CLASS__ macro in C++?
Is there a __CLASS__ macro in C++ which gives the class name similar to __FUNCTION__ macro which gives the function name
...
How to make graphics with transparent background in R using ggplot2?
...# for the inside of the boxplot
)
Fastest way is using using rect, as all the rectangle elements inherit from rect:
p <- p +
theme(
rect = element_rect(fill = "transparent") # all rectangles
)
p
More controlled way is to use options of theme:
p <- p +
theme(
...
d3 axis labeling
...eet to style these labels as you like, either together (.label) or individually (.x.label, .y.label).
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Ruby on Rails: Delete multiple hash keys
...re unaware of the Hash#except method ActiveSupport adds to Hash.
It would allow your code to be simplified to:
redirect_to my_path(params.except(:controller, :action, :other_key))
Also, you wouldn't have to monkey patch, since the Rails team did it for you!
...
How do I revert all local changes in Git managed project to previous state?
...to the index (i.e., that you have added), do this. Warning this will reset all of your unpushed commits to master!:
git reset
If you want to revert a change that you have committed, do this:
git revert <commit 1> <commit 2>
If you want to remove untracked files (e.g., new files, ge...