Tutorial by Examples: e

Draw samples from a normal (gaussian) distribution # Generate 5 random numbers from a standard normal distribution # (mean = 0, standard deviation = 1) np.random.randn(5) # Out: array([-0.84423086, 0.70564081, -0.39878617, -0.82719653, -0.4157447 ]) # This result can also be achieved with t...

Install npm is bundled with Node.js, so if you install Node.js you'll automatically have npm installed too. You can choose between a Current and a LTS version Windows For Microsoft Windows you can download a MSI installer from https://nodejs.org/en/download/. OS X For Apple OS X you can downloa...

.htaccess can be used to set a custom error pages that matches the theme of your website instead of seeing a white error page with black techno-babble when users end up on at a page with an error server response code. The error page can be any browser parseable file, including (But not limited to)...

In the condition of the for and while loops, it's also permitted to declare an object. This object will be considered to be in scope until the end of the loop, and will persist through each iteration of the loop: for (int i = 0; i < 5; ++i) { do_something(i); } // i is no longer in scope...

The following method computes the Nth Fibonacci number using recursion. public int fib(final int n) { if (n > 2) { return fib(n - 2) + fib(n - 1); } return 1; } The method implements a base case (n <= 2) and a recursive case (n>2). This illustrates the use of re...

Overload resolution partitions the cost of passing an argument to a parameter into one of four different categorizes, called "sequences". Each sequence may include zero, one or several conversions Standard conversion sequence void f(int a); f(42); User defined conversion seque...

If your class doesn't implement a specific overloaded operator for the argument types provided, it should return NotImplemented (note that this is a special constant, not the same as NotImplementedError). This will allow Python to fall back to trying other methods to make the operation work: When...

While The most trivial loop type. Only drawback is there is no intrinsic clue to know where you are in the loop. /// loop while the condition satisfies while(condition) { /// do something } Do Similar to while, but the condition is evaluated at the end of the loop instead of the beginn...

iex([email protected])> Node.list [:"[email protected]"]

Start two named nodes in two terminal windows: >iex --name [email protected] iex([email protected])> >iex --name [email protected] iex([email protected])> Connect two nodes by instructing one node to connect: iex([email protected])> Node.connect :"[email protected]" true The two n...

Start a named process on one IP address: $ iex --name [email protected] --cookie chocolate iex([email protected])> Node.ping :"[email protected]" :pong iex([email protected])> Node.list [:"[email protected]"] Start another named process on a different IP address: $ iex ...

Files and directories (another name for folders) are at the heart of Linux, so being able to create, view, move, and delete them from the command line is very important and quite powerful. These file manipulation commands allow you to perform the same tasks that a graphical file explorer would perfo...

Use the HTML or <audio> element to embed video/audio content in a document. The video/audio element contains one or more video/audio sources. To specify a source, use either the src attribute or the <source> element; the browser will choose the most suitable one. Audio tag example: &...

By recursion let rec sumTotal list = match list with | [] -> 0 // empty list -> return 0 | head :: tail -> head + sumTotal tail The above example says: "Look at the list, is it empty? return 0. Otherwise it is a non-empty list. So it could be [1], [1; 2], [1; 2; 3] ...

You can open several content managers at the same time: with open(input_path) as input_file, open(output_path, 'w') as output_file: # do something with both files. # e.g. copy the contents of input_file into output_file for line in input_file: output_file.write(line...

Code that uses generics has many benefits over non-generic code. Below are the main benefits Stronger type checks at compile time A Java compiler applies strong type checking to generic code and issues errors if the code violates type safety. Fixing compile-time errors is easier than fixing runt...

Install the necessary Python Library via: $ pip install elasticsearch Connect to Elasticsearch, Create a Document (e.g. data entry) and "Index" the document using Elasticsearch. from datetime import datetime from elasticsearch import Elasticsearch # Connect to Elasticsearch using ...

Example uses basic HTTP syntax. Any <#> in the example should be removed when copying it. You can use the _cat APIs to get a human readable, tabular output for various reasons. GET /_cat/health?v <1> The ?v is optional, but it implies that you want "verbose" output. _...

Free version of SSH protocol implementation, OpenSSH is available in all the Linux distributions. It consists of the server and client packages. Installation On Debian-based Linux, you can install openssh using # apt-get install openssh-server openssh-client On RHEL/CentOS you need to use yum:...

One can select rows and columns of a dataframe using boolean arrays. import pandas as pd import numpy as np np.random.seed(5) df = pd.DataFrame(np.random.randint(100, size=(5, 5)), columns = list("ABCDE"), index = ["R" + str(i) for i in range(5)]) print (...