Tutorial by Examples: ces

We can reference a function without actually calling it by prefixing the function's name with ::. This can then be passed to a function which accepts some other function as a parameter. fun addTwo(x: Int) = x + 2 listOf(1, 2, 3, 4).map(::addTwo) # => [3, 4, 5, 6] Functions without a receiv...

When implementing more than one interface that have methods of the same name that include default implementations, it is ambiguous to the compiler which implementation should be used. In the case of a conflict, the developer must override the conflicting method and provide a custom implementation. ...

Slice syntax is i:j:k where i is the starting index (inclusive), j is the stopping index (exclusive) and k is the step size. Like other python data structures, the first element has an index of 0: x = np.arange(10) x[0] # Out: 0 x[0:4] # Out: array([0, 1, 2, 3]) x[0:4:2] # Out:array([0, 2...

If an object is defined with static, thread, or automatic storage duration, and it has a character type, either: char, unsigned char, or signed char, it may not be accessed by a non-character type. In the below example a char array is reinterpreted as the type int, and the behavior is undefined on e...

Avoid destructive operations on quoted objects. Quoted objects are literal objects. They are possibly embedded in the code in some way. How this works and the effects of modifications are unspecified in the Common Lisp standard, but it can have unwanted consequences like modifying shared data, tryin...

Using the Android API 23 or higher, very often such situation can be seen: This situation is caused by the structural change of the Android API regarding getting the resources. Now the function: public int getColor(@ColorRes int id, @Nullable Theme theme) throws NotFoundException should...

git diff myfile.txt Shows the changes between the previous commit of the specified file (myfile.txt) and the locally-modified version that has not yet been staged. This also works for directories: git diff documentation The above shows the changes between the previous commit of all files in ...

Before the C compiler starts compiling a source code file, the file is processed in a preprocessing phase. This phase can be done by a separate program or be completely integrated in one executable. In any case, it is invoked automatically by the compiler before compilation proper begins. The prepro...

(loop for i in '(one two three four five six) do (print i)) (loop for i in '(one two three four five six) by #'cddr do (print i)) ;prints ONE THREE FIVE (loop for i on '(a b c d e f g) do (print (length i))) ;prints 7 6 5 4 3 2 1 (loop for i on '(a b c d e f g) by #'cddr ...

Sometimes it's necessary to be able to extract values from an object using only references (ie. without transferring ownership). struct Token { pub id: u32 } struct User { pub token: Option<Token> } fn main() { // Create a user with an arbitrary token let user = User...

A sequence is very much like a list: it is an immutable object that can give you its first element or the rest of its elements in constant time. You can also construct a new sequence from an existing sequence and an item to stick at the beginning. You can test whether something is a sequence using ...

The android:process field defines the name of the process where the service is to run. Normally, all components of an application run in the default process created for the application. However, a component can override the default with its own process attribute, allowing you to spread your applicat...

tl;dr : Create a base class that defines two user objects (say user and another_user). Create your other models and define three Client instances. self.client : Representing user logged in browser self.another_client : Representing another_user 's client self.unlogged_client : Representing unlo...

SharedPreferences Manager (Singleton) class to read and write all types of data. import android.content.Context; import android.content.SharedPreferences; import android.util.Log; import com.google.gson.Gson; import java.lang.reflect.Type; /** * Singleton Class for accessing SharedPref...

Type hinting for classes and interfaces was added in PHP 5. Class type hint <?php class Student { public $name = 'Chris'; } class School { public $name = 'University of Edinburgh'; } function enroll(Student $student, School $school) { echo $student->name . ' is b...

You can access SharedPreferences in several ways: Get the default SharedPreferences file: import android.preference.PreferenceManager; SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this); Get a specific SharedPreferences file: public static final String PREF_FILE_NAM...

Slices are the typical way go programmers store lists of data. To declare a slice variable use the []Type syntax. var a []int To declare and initialize a slice variable in one line use the []Type{values} syntax. var a []int = []int{3, 1, 4, 1, 5, 9} Another way to initialize a slice is with...

An unnamed namespace can be used to ensure names have internal linkage (can only be referred to by the current translation unit). Such a namespace is defined in the same way as any other namespace, but without the name: namespace { int foo = 42; } foo is only visible in the translation uni...

getPreferences(int) returns the preferences saved by Activity's class name as described in the docs : Retrieve a SharedPreferences object for accessing preferences that are private to this activity. This simply calls the underlying getSharedPreferences(String, int) method by passing in this acti...

To spawn a new process in which you need unbuffered output (e.g. long-running processes which might print output over a period of time rather than printing and exiting immediately), use child_process.spawn(). This method spawns a new process using a given command and an array of arguments. The retu...