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What is an “unwrapped value” in Swift?
...e bang operator when the value is nil your application will crash.
And in order to use these variables at all in some sort or mathematical operation they must be unwrapped in order to do so.
For instance, in Swift only valid number data types of the same kind may be operated on each other. When yo...
How do you perform a left outer join using linq extension methods
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You need to remember to Order your joined table or the .FirstOrDefault() is going to get a random row from the multiple rows that might match the join criteria, whatever the database happens to find first.
– Chris Moschini
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Read entire file in Scala?
...e to the party, but I'd hate for people not to know they can do "io.File("/etc/passwd").slurp" in trunk.
– psp
Aug 26 '09 at 3:48
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Relational Database Design Patterns? [closed]
...versally applicable data models (employees, accounts, shipping, purchases, etc), Volume 2 contains industry specific data models (accounting, healthcare, etc), Volume 3 provides data model patterns.
Finally, while this book is ostensibly about UML and Object Modelling, Peter Coad's Modeling in Colo...
Get list from pandas DataFrame column headers
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Importantly, this preserves the column order.
– WindChimes
Jan 25 '16 at 13:07
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Image comparison - fast algorithm
... if a good match is found at the faster level.
file-hash based (md5,sha1,etc) for exact duplicates
perceptual hashing (phash) for rescaled images
feature-based (SIFT) for modified images
I am having very good results with phash. The accuracy is good for rescaled images. It is not good ...
How to add external library in IntelliJ IDEA?
...have a smaller
screen like me, you may have to drag resize to the right in order to
see it)
From the dropdown of Add options, choose "Library". A "Choose
Libraries" dialog will appear.
Press "New Library..."
Choose a suitable title for the library
Press "Attach Classes..."
Choose the Jar from your l...
pip install mysql-python fails with EnvironmentError: mysql_config not found
...e path, but I think you're better off adding it permanently (ie add it to /etc/paths) if you plan to install MySQL-python in another environment.
(tested in OSX Mountain Lion)
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What are deferred objects?
...ynchronous nature leads to a problem when you want to execute things in an order, for example, you want to print something after Y (asynch) is done executing or done fetching data. Here jQuery provide us with Deffered Object. Basically, jQuery has taken care of all boilerplate code that usually we w...
HashSet vs. List performance
... Even if you say your List<T> wouldn't have duplicates and iteration order doesn't matter making it comparable to a HashSet<T>, its still a poor choice to use List<T> because its relatively less fault tolerant.
That said, I will inspect some other aspects of performance,
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