InvocationExpression class allows invocation of other lambda expressions that are parts of the same Expression tree.
You create them with static Expression.Invoke method.
Problem
We want to get on the items which have "car" in their description. We need to check it for null before searc...
The viewport meta tag tells a device to set the viewable area to the width of the device screen. It also sets the initial scale to normal (not zoomed in or out).
<meta name="viewport" content="width=device-width">
or
<meta name="viewport" content="wid...
Most Rx operators take an optional scheduler on which to schedule their future iterations. If not supplied they will use their default configured scheduler. Supplying a scheduler can be useful for testing purposes in which we like to talk about virtual time instead of real time for speed of test exe...
We have a set of jobs J={a,b,c,d,e,f,g}. Let j in J be a job than its start at sj and ends at fj. Two jobs are compatible if they don't overlap. A picture as example:
The goal is to find the maximum subset of mutually compatible jobs. There are several greedy approaches for this problem:
Earli...
Matrix chain multiplication is an optimization problem that can be solved using dynamic programming. Given a sequence of matrices, the goal is to find the most efficient way to multiply these matrices. The problem is not actually to perform the multiplications, but merely to decide the sequence of t...
This package generates a file that your IDE understands, so it can provide accurate autocompletion. Generation is done based on the files in your project.
Read more about this here
Ruby 2.3.0 added the safe navigation operator, &.. This operator is intended to shorten the paradigm of object && object.property && object.property.method in conditional statements.
For example, you have a House object with an address property, and you want to find the street_n...
Viridis (named after the chromis viridis fish) is a recently developed color scheme for the Python library matplotlib (the video presentation by the link explains how the color scheme was developed and what are its main advantages). It is seamlessly ported to R.
There are 4 variants of color scheme...
Quite often there is a need to glimpse the chosen color palette. One elegant solution is the following self defined function:
color_glimpse <- function(colors_string){
n <- length(colors_string)
hist(1:n,breaks=0:n,col=colors_string)
}
An example of use
color_glimpse(...
I am gonna assume you already know about adding gradle dependencies firebase in android studio. If you don't just follow the guide from here. Add your app in firebase console, gradle sync android studio after adding dependencies. All dependencies are not needed just firebase database and firebase au...
When you have a huge JSON database, adding a value event listener doesn't make sense. It will return the huge JSON and parsing it would be time consuming. In such cases we can use pagination and fetch part of data and display or process it. Kind of like lazy loading or like fetching old chats when u...
In [1]: df = pd.DataFrame({'A': [1, 2, 3], 'B': [1.0, 2.0, 3.0], 'C': ['a', 'b', 'c'],
'D': [True, False, True]})
In [2]: df
Out[2]:
A B C D
0 1 1.0 a True
1 2 2.0 b False
2 3 3.0 c True
Getting a python list from a series:
In [3]: df['...
When we put the control of Label, the Label does not provide any event.
<Label x:Name="lblSignUp Text="Dont't have account?"/>
as shown the Label only display purpose only.
When the user want to replace Button with Label, then we give the event for Label.
As shown below:
XA...
Controller::renderAjax() method can be used to respond to an Ajax request. This method is similar to renderPartial() except that it will inject into the rendering result with JS/CSS scripts and files which are registered with the view
Assume we have login form in a view file:
<?php
use yii\hel...
Overview: There are typically two types of SAS Deployments:
SAS Foundation only installation (BASE SAS). This is typically is installed on a PC. It does not run any server software.
SAS Planned Deployment for their server architecture which will install the SAS server environment along wit...
Description:
mov copies values of bits from source argument to destination argument.
Common source/destination are registers, usually the fastest way to manipulate values with[in] CPU.
Another important group of source_of/destination_for values is computer memory.
Finally some immediate values m...
For a circular View (in this case TextView) create a drawble round_view.xml in drawble folder:
<?xml version="1.0" encoding="utf-8"?>
<shape
xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval">
<solid...
Clearing the content of a web element: (note - when simulating user actions in tests, it's better to send backspace, see next action)
interactionWebElement.clear();
Entering data - simulating sending keystrokes:
interactionWebElement.sendKeys("Text");
interactionWebElement.sendKeys(K...
Although not necessary in PHP however it is a very good practice to initialize variables. Uninitialized variables have a default value of their type depending on the context in which they are used:
Unset AND unreferenced
var_dump($unset_var); // outputs NULL
Boolean
echo($unset_bool ? "tr...
