Tutorial by Examples: l

First, references will be added to the CLR assemblies that will be used. import clr clr.AddReference('System.Windows.Forms') Next the names we will use are imported. from System.Windows.Forms import Application, Form A class will be created for the Hello World form using Form as its subclas...

This example shows a minimal Mockito test using a mocked ArrayList: import static org.mockito.Mockito.*; import static org.junit.Assert.*; import java.util.ArrayList; import org.junit.Test; import org.junit.runner.RunWith; import org.mockito.Mock; import org.mockito.runners.MockitoJUnitRu...

To modify an XML file with XDocument, you load the file into a variable of type XDocument, modify it in memory, then save it, overwriting the original file. A common mistake is to modify the XML in memory and expect the file on disk to change. Given an XML file: <?xml version="1.0" e...

Closures are inline anonymous methods that have the ability to use Parent method variables and other anonymous methods which are defined in the parent's scope. In essence, a closure is a block of code which can be executed at a later time, but which maintains the environment in which it was firs...

The IEnumerable<T> interface has a single method, GetEnumerator(), which returns an IEnumerator<T>. While the yield keyword can be used to directly create an IEnumerable<T>, it can also be used in exactly the same way to create an IEnumerator<T>. The only thing that changes ...

Some languages include a list data structure. Common Lisp, and other languages in the Lisp family, make extensive use of lists (and the name Lisp is based on the idea of a LISt Processor). However, Common Lisp doesn't actually include a primitive list datatype. Instead, lists exist by convention....

A cons cell, also known as a dotted pair (because of its printed representation), is simply a pair of two objects. A cons cell is created by the function cons, and elements in the pair are extracted using the functions car and cdr. (cons "a" 4) For instance, this returns a pair whose ...

Following is most basic expression tree that is created by lambda. Expression<Func<int, bool>> lambda = num => num == 42; To create expression trees 'by hand', one should use Expression class. Expression above would be equivalent to: ParameterExpression parameter = Expression.Pa...

Swift timer.fire() Objective-C [timer fire]; Calling the fire method causes an NSTimer to perform the task it would have usually performed on a schedule. In a non-repeating timer, this will automatically invalidate the timer. That is, calling fire before the time interval is up will result ...

Swift timer.invalidate() Objective-C [timer invalidate]; This will stop the timer from firing. Must be called from the thread the timer was created in, see Apple's notes: You must send this message from the thread on which the timer was installed. If you send this message from another thr...

Keyword for storing the Boolean values true and false. bool is an alias of System.Boolean. The default value of a bool is false. bool b; // default value is false b = true; // true b = ((5 + 2) == 6); // false For a bool to allow null values it must be initialized as a bool?. The default val...

For example, if t1 is currently not an InnoDB table, this statement changes its storage engine to InnoDB: ALTER TABLE t1 ENGINE = InnoDB; If the table is already InnoDB, this will rebuild the table and its indexes and have an effect similar to OPTIMIZE TABLE. You may gain some disk space improv...

x = tf.constant(1.) bool = tf.constant(True) res = tf.cond(bool, lambda: tf.add(x, 1.), lambda: tf.add(x, 10.)) # sess.run(res) will give you 2.

The two functions fn1 and fn2 can return multiple tensors, but they have to return the exact same number and types of outputs. x = tf.constant(1.) bool = tf.constant(True) def fn1(): return tf.add(x, 1.), x def fn2(): return tf.add(x, 10.), x res1, res2 = tf.cond(bool, fn1, fn2)...

Below won't work on a Windows machine $file = $request->file('file_upload'); $sampleName = 'UserUpload'; $destination = app_path() . '/myStorage/'; $fileName = $sampleName . '-' . date('Y-m-d-H:i:s') . '.' . $file->getClientOriginalExtension(); $file->move($destination, $fileName); ...

The following values are considered falsey, in that they evaluate to False when applied to a boolean operator. None False 0, or any numerical value equivalent to zero, for example 0L, 0.0, 0j Empty sequences: '', "", (), [] Empty mappings: {} User-defined types where the __bool__ o...

Like lists and tuples, you can include a trailing comma in your dictionary. role = {"By day": "A typical programmer", "By night": "Still a typical programmer", } PEP 8 dictates that you should leave a space between the trailing comma and the closi...

There are three kinds of numeric RangeFields in Python. IntegerField, BigIntegerField, and FloatField. They convert to psycopg2 NumericRanges, but accept input as native Python tuples. The lower bound is included and the upper bound is excluded. class Book(models.Model): name = CharField(max_l...

add 'django.contrib.postgres' to your INSTALLED_APPS install psycopg2

It's simpler and easier to input values as a Python tuple instead of a NumericRange. Book.objects.create(name='Pro Git', ratings_range=(5, 5)) Alternative method with NumericRange: Book.objects.create(name='Pro Git', ratings_range=NumericRange(5, 5))