Tutorial by Examples: nd

There are many querying operations on maps. member :: Ord k => k -> Map k a -> Bool yields True if the key of type k is in Map k a: > Map.member "Alex" $ Map.singleton "Alex" 31 True > Map.member "Jenny" $ Map.empty False notMember is similar: &g...

Undo Command:Descriptionuu,undoUndo the most recent change5uUndo the five most recent changes (use any number) Please be aware that in Vim, the 'most recent change' varies according to the mode you are in. If you enter Insert Mode (i) and type out an entire paragraph before dropping back to Normal...

In Vim, these operations are handled differently from what you might be used to in almost any other modern editor or word processor (Ctrl-C, Ctrl-X, Ctrl-V). To understand, you need to know a little about registers and motions. Note: this section will not cover Visual Mode copying and cutting or ra...

This is very similar to using an Application subclass and overriding the attachBaseContext() method. However, using this method, you don't need to override attachBaseContext() as this is already done in the MultiDexApplication superclass. Extend MultiDexApplication instead of Application: package...

Unlike a parallel for-loop (parfor), which takes the iterations of a loop and distributes them among multiple threads, a single program, multiple data (spmd) statement takes a series of commands and distributes them to all the threads, so that each thread performs the command and stores the results....

Using Alternatives Many Linux distributions use the alternatives command for switching between different versions of a command. You can use this for switching between different versions of Java installed on a machine. In a command shell, set $JDK to the pathname of a newly installed JDK; e.g....

Given a DataFrame with MultiIndex columns # build an example DataFrame midx = pd.MultiIndex(levels=[['zero', 'one'], ['x','y']], labels=[[1,1,0,],[1,0,1,]]) df = pd.DataFrame(np.random.randn(2,3), columns=midx) In [2]: df Out[2]: one zero y x ...

Start with a standard DataFrame df = pd.DataFrame(np.random.randn(2,3), columns=['a','b','c']) In [91]: df Out[91]: a b c 0 -0.911752 -1.405419 -0.978419 1 0.603888 -1.187064 -0.035883 Now to change to MultiIndex, create a MultiIndex object and assign it to df....

MultiIndex can also be used to create DataFrames with multilevel columns. Just use the columns keyword in the DataFrame command. midx = pd.MultiIndex(levels=[['zero', 'one'], ['x','y']], labels=[[1,1,0,],[1,0,1,]]) df = pd.DataFrame(np.random.randn(6,4), columns=midx) In [86]: df Out[86]: ...

Dependencies can be added for specific product flavors in a similar fashion as build configurations. android { ... productFlavors { flavor1 { //... } flavor2 { //... } } } dependencies { flavor1Compile 'com.and...

Use .get(key) to get value by key and .set(key, value) to assign a value to a key. If the element with the specified key doesn't exist in the map, .get() returns undefined. .set() method returns the map object, so you can chain .set() calls. const map = new Map(); console.log(map.get(1)); // und...

Building project dependencies can sometimes be a tedious task. Instead of publishing a package version to NPM and installing the dependency to test the changes, use npm link. npm link creates a symlink so the latest code can be tested in a local environment. This makes testing global tools and proje...

The %timeit magic runs the given code many times, then returns the speed of the fastest result. In [1]: %timeit sum(range(100000)) 100 loops, best of 3: 2.91 ms per loop The %%timeit cell magic can be used to time blocks of code. In [2]: %%timeit ...: a = 0 ...: for i in range(100000):...

R provides two additional looping constructs, while and repeat, which are typically used in situations where the number of iterations required is indeterminate. The while loop The general form of a while loop is as follows, while (condition) { ## do something ## in loop body } whe...

For a class Person like: public class Person { public string Name { get; set; } public int Age { get; set; } public string Clothes { get; set; } } var person1 = new Person { Name = "Jon", Age = 20, Clothes = "some clothes" }; var person2 = new Person { Name ...

For given type Person: public class Person { public string Name { get; set; } public int Age { get; set; } public string Clothes { get; set; } } List<Person> persons = new List<Person> { new Person{ Name = "Jon", Age = 20, Clothes = "some clothes...

These types are in all versions of SQL Server datetime smalldatetime These types are in all versions of SQL Server after SQL Server 2012 date datetimeoffset datetime2 time

This example shows how to render text along an arc. It includes how you can add functionality to the CanvasRenderingContext2D by extending its prototype. This examples is derived from the stackoverflow answer Circular Text. Example rendering Example code The example adds 3 new text renderi...

Generally execute() command is used for fire and forget calls (without need of analyzing the result) and submit() command is used for analyzing the result of Future object. We should be aware of key difference of Exception Handling mechanisms between these two commands. Exceptions from submit() ar...

C++14 C++14 introduced a standard way of deprecating functions via attributes. [[deprecated]] can be used to indicate that a function is deprecated. [[deprecated("reason")]] allows adding a specific reason which can be shown by the compiler. void function(std::unique_ptr<A> &&a...