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Difference between case object and object
...of serialization
a prettier default implementation of toString, and
the small amount of functionality that they get from automatically inheriting from scala.Product.
Pattern matching, equals and hashCode don't matter much for singletons (unless you do something really degenerate), so you're pre...
How can I convert an RGB image into grayscale in Python?
...
SciPy's image I/O is literally PIL/Pillow. Hence, testing SciPy is effectively retesting PIL/Pillow with negligible overhead introduced by SciPy's wrapper functions. It would have been much more useful to substitute OpenCV (which does not leverage PIL...
How to test that no exception is thrown?
... test your functionality: if an exception is thrown the test will automatically fail. If no exception is thrown, your tests will all turn up green.
I have noticed this question garners interest from time to time so I'll expand a little.
Background to unit testing
When you're unit testing it's imp...
How to copy from current position to the end of line in vi
...
If you don't want to include the line break with the yank, you can use yg_. (Or in your case, "*yg_)
Basically, just recognize there's a difference between $ and g_ movement-wise. It's helped me on numerous occasions.
sha...
Using Python String Formatting with Lists
...rmat with print() to iterate a list.
How about this (python 3.x):
sample_list = ['cat', 'dog', 'bunny', 'pig']
print("Your list of animals are: {}, {}, {} and {}".format(*sample_list))
Read the docs here on using format().
...
Join/Where with LINQ and Lambda
...re post.ID == id
select new { Post = post, Meta = meta };
If you're really stuck on using lambdas though, your syntax is quite a bit off. Here's the same query, using the LINQ extension methods:
var id = 1;
var query = database.Posts // your starting point - table in the "from" statement
...
How to format a java.sql Timestamp for displaying?
...SQL and want the database itself to perform the conversion, use this:
DATE_FORMAT(date,format)
If you prefer to format using Java, use this:
java.text.SimpleDateFormat
SimpleDateFormat dateFormat = new SimpleDateFormat("M/dd/yyyy");
dateFormat.format( new Date() );
...
Connect Java to a MySQL database
...
Here's a step by step explanation how to install MySQL and JDBC and how to use it:
Download and install the MySQL server. Just do it the usual way. Remember the port number whenever you've changed it. It's by default 3306.
Download the JDBC driver and put in classpath...
How do I set bold and italic on UILabel of iPhone/iPad?
...t {
return with([.traitBold, .traitItalic])
}
func with(_ traits: UIFontDescriptor.SymbolicTraits...) -> UIFont {
guard let descriptor = self.fontDescriptor.withSymbolicTraits(UIFontDescriptor.SymbolicTraits(traits).union(self.fontDescriptor.symbolicTraits)) else {
...
What is “lifting” in Scala?
...ethod into a function by applying the underscore
scala> val f = times2 _
f: Int => Int = <function1>
scala> f(4)
res0: Int = 8
Note the fundamental difference between methods and functions. res0 is an instance (i.e. it is a value) of the (function) type (Int => Int)
Functors
...