Tutorial by Examples: s

import pandas as pd import numpy as np import matplotlib.pyplot as plt # I want 7 days of 24 hours with 60 minutes each periods = 7 * 24 * 60 tidx = pd.date_range('2016-07-01', periods=periods, freq='T') # ^ ^ # | ...

Consider the following example: @sky-blue: #87ceeb; @dark-sky-blue: @sky-blue + #333; body { background-color: @dark-sky-blue; } The above example gives you: body { background-color: #baffff; } Here it explains how to declare a variable and also make operations on a particular va...

C++11 The std::is_same<T, T> type relation is used to compare two types. It will evaluate as boolean, true if the types are the same and false if otherwise. e.g. // Prints true on most x86 and x86_64 compilers. std::cout << std::is_same<int, int32_t>::value << "\n&qu...

C++11 There are a number of different type traits that compare more general types. Is Integral: Evaluates as true for all integer types int, char, long, unsigned int etc. std::cout << std::is_integral<int>::value << "\n"; // Prints true. std::cout << std::is_in...

C++11 Type properties compare the modifiers that can be placed upon different variables. The usefulness of these type traits is not always obvious. Note: The example below would only offer an improvement on a non-optimizing compiler. It is a simple a proof of concept, rather than complex example. ...

aiohttp provides asynchronous websockets. Python 3.x3.5 import asyncio from aiohttp import ClientSession with ClientSession() as session: async def hello_world(): websocket = await session.ws_connect("wss://echo.websocket.org") websocket.send_str("Hell...

aiohttp.ClientSession may be used as a parent for a custom WebSocket class. Python 3.x3.5 import asyncio from aiohttp import ClientSession class EchoWebSocket(ClientSession): URL = "wss://echo.websocket.org" def __init__(self): super().__init__() self....

6 In ECMAScript 6, when using the module syntax (import/export), each file becomes its own module with a private namespace. Top-level functions and variables do not pollute the global namespace. To expose functions, classes, and variables for other modules to import, you can use the export keyword....

can either pass string of the json, or a filepath to a file with valid json In [99]: pd.read_json('[{"A": 1, "B": 2}, {"A": 3, "B": 4}]') Out[99]: A B 0 1 2 1 3 4 Alternatively to conserve memory: with open('test.json') as f: data = pd.Da...

def to_flare_json(df, filename): """Convert dataframe into nested JSON as in flare files used for D3.js""" flare = dict() d = {"name":"flare", "children": []} for index, row in df.iterrows(): parent = row[...

By default, npm installs the latest available version of modules according to each dependencies' semantic version. This can be problematic if a module author doesn't adhere to semver and introduces breaking changes in a module update, for example. To lock down each dependencies' version (and the ve...

There are two ways to create object mocked by Mockito: via annotation via mock function Via annotation: With a JUnit test runner: @RunWith(MockitoJUnitRunner.class) public class FooTest { @Mock private Bar barMock; // ... } You can also use Mockito's JUnit @Rule, which...

There have been many releases of Java since the original Java 1.0 release in 1995. (Refer to Java version history for a summary.) However most releases have passed their official End Of Life dates. This means that the vendor (typically Oracle now) has ceased new development for the release, and n...

One method for creating recursive lambda functions involves assigning the function to a variable and then referencing that variable within the function itself. A common example of this is the recursive calculation of the factorial of a number - such as shown in the following code: lambda_factorial ...

Input record separator can be specified with -0 switch (zero, not capital O). It takes an octal or hexadecimal number as value. Any value 0400 or above will cause Perl to slurp files, but by convention, the value used for this purpose is 0777. perl -0777 -e 'my $file = <>; print length($file)...

In order to start using Sequelize, you must first install the Sequelize package using the Node Package Manager (npm). Install sequelize module Add --save option to store module in package.json npm install sequelize Next, depending on which database system you wish to use with Sequelize, instal...

%paste This is the primary Magic Method for pasting. It directly pastes text from the system clipboard, intelligently handling common issues with newlines and indentation. %cpaste If you are using IPython via SSH, use %cpaste instead, as it does not need to access the remote system clipbo...

Sometimes it's useful to check if a field is present or absent on your JSON to avoid some JSONException on your code. To achieve that, use the JSONObject#has(String) or the method, like on the following example: Sample JSON { "name":"James" } Java code String jsonStr...

Java release naming is a little confusing. There are actually two systems of naming and numbering, as shown in this table: JDK versionMarketing namejdk-1.0JDK 1.0jdk-1.1JDK 1.1jdk-1.2J2SE 1.2......jdk-1.5J2SE 1.5 rebranded Java SE 5jdk-1.6Java SE 6jdk-1.7Java SE 7jdk-1.8Java SE 8jdk-91Java SE 9 (n...

Bootstrap provides multiple classes for styling buttons and making them stand out. Bootstrap buttons can be created by adding the .btn class to an element. Bootstrap ClassRole (color).btn-defaultStandard button (white).btn-primaryProvides extra visual weight and identifies the primary action (blue...