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First of all, we need to add our first Fragment at the beginning, we should do it in the onCreate() method of our Activity: if (null == savedInstanceState) { getSupportFragmentManager().beginTransaction() .addToBackStack("fragmentA") .replace(R.id.container, FragmentA.n...

Detailed instructions on getting razor set up or installed.

So let's suppose you want to iterate only between some specific lines of a file You can make use of itertools for that import itertools with open('myfile.txt', 'r') as f: for line in itertools.islice(f, 12, 30): # do something here This will read through the lines 13 to 20 as i...

You can use flatMap(_:) in a similar manner to map(_:) in order to create an array by applying a transform to a sequence's elements. extension SequenceType { public func flatMap<T>(@noescape transform: (Self.Generator.Element) throws -> T?) rethrows -> [T] } The difference with...

sed -i s/"what to replace"/"with what to replace"/g $file We use -i to select in-place editing on the $file file. In some systems it is required to add suffix after -i flag which will be used to create backup of original file. You can add empty string like -i '' to omit the b...

ansible -i hosts -m ping targethost -i hosts defines the path to inventory file targethost is the name of the host in the hosts file

Inventory is the Ansible way to track all the systems in your infrastructure. Here is a simple static inventory file containing a single system and the login credentials for Ansible. [targethost] 192.168.1.1 ansible_user=mrtuovinen ansible_ssh_pass=PassW0rd Write these lines for example to host...

Here's how you can destructure a vector: (def my-vec [1 2 3]) Then, for example within a let block, you can extract values from the vector very succinctly as follows: (let [[x y] my-vec] (println "first element:" x ", second element: " y)) ;; first element: 1 , second ele...

Here's how you can destructure a map: (def my-map {:a 1 :b 2 :c 3}) Then, for example, within a let block you can extract values from the map very succinctly as follows: (let [{x :a y :c} my-map] (println ":a val:" x ", :c val: " y)) ;; :a val: 1 , :c val: 3 Notice th...

Let's say you have a vector like so: (def my-vec [1 2 3 4 5 6]) And you want to extract the first 3 elements and get the remaining elements as a sequence. This can be done as follows: (let [[x y z & remaining] my-vec] (println "first:" x ", second:" y "third:&quot...

The Action Attribute The action attribute defines the action to be performed when the form is submitted, which usually leads to a script that collects the information submitted and works with it. if you leave it blank, it will send it to the same file <form action="action.php"> ...

Create a class inheriting from Exception: class FooException(Exception): pass try: raise FooException("insert description here") except FooException: print("A FooException was raised.") or another exception type: class NegativeError(ValueError): pass ...

If the mimetype of the HTTP request is application/json, calling request.get_json() will return the parsed JSON data (otherwise it returns None) from flask import Flask, jsonify app = Flask(__name__) @app.route('/api/echo-json', methods=['GET', 'POST', 'DELETE', 'PUT']) ...

public void iterateAndFilter() throws IOException { Path dir = Paths.get("C:/foo/bar"); PathMatcher imageFileMatcher = FileSystems.getDefault().getPathMatcher( "regex:.*(?i:jpg|jpeg|png|gif|bmp|jpe|jfif)"); try (Direc...

# For Python 2 compatibility. from __future__ import print_function import lxml.html import requests def main(): r = requests.get("https://httpbin.org") html_source = r.text root_element = lxml.html.fromstring(html_source) # Note root_element.xpath() gives a *...

Given a String and a Character let text = "Hello World" let char: Character = "o" We can count the number of times the Character appears into the String using let sensitiveCount = text.characters.filter { $0 == char }.count // case-sensitive let insensitiveCount = text.low...

Add gem to the Gemfile: gem 'devise' Then run the bundle install command. Use command $ rails generate devise:install to generate required configuration file. Set up the default URL options for the Devise mailer in each environment In development environment add this line: config.action_mailer...

Boolean(0) === false Boolean(0) will convert the number 0 into a boolean false. A shorter, but less clear, form: !!0 === false

To convert a string to boolean use Boolean(myString) or the shorter but less clear form !!myString All strings except the empty string (of length zero) are evaluated to true as booleans. Boolean('') === false // is true Boolean("") === false // is true Boolean('0') === fals...

If the values in a container have certain operators already overloaded, std::sort can be used with specialized functors to sort in either ascending or descending order: C++11 #include <vector> #include <algorithm> #include <functional> std::vector<int> v = {5,1,2,4,3};...