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Difference between Observer, Pub/Sub, and Data Binding
...the shape of a specific function/method. The observable is the one who provides notifications, and the observer receives those notifications. In .net, the observable can expose an event and the observer subscribes to that event with an "event handler" shaped hook. No assumptions are made about the s...
Why does the C# compiler not fault code where a static method calls an instance method?
...7.3 (May 2018). In What's new in C# 7.3, the section Improved overload candidates, item 1, it is explained how the overload resolution rules have changed so that non-static overloads are discarded early. So the below answer (and this entire question) has mostly only historical interest by now!
(P...
Referencing a string in a string array resource with xml
...an, but there seems to be a workaround:.
If you take a look into the Android Resource here:
http://developer.android.com/guide/topics/resources/string-resource.html
You see than under the array section (string array, at least), the "RESOURCE REFERENCE" (as you get from an XML) does not specify a ...
How do RVM and rbenv actually work?
...ng. Every time you install a new version of Ruby or install a gem that provides a command, run rbenv rehash to make sure any new commands are shimmed.
These shims live in a single directory (~/.rbenv/shims by default). To use rbenv, you need only add the shims directory to the front of your PATH:
...
Can I make a function available in every controller in angular?
...e a utility function foo that I want to be able to call from anywhere inside of my ng-app declaration. Is there someway I can make it globally accessible in my module setup or do I need to add it to the scope in every controller?
...
what is the difference between a portlet and a servlet?
...only through the portal page
which holds the portlet.
Portlets can be provided with controls to manipulate its window states
or portlet modes.
Multiple instances of a single portlet can be placed onto the same
page.
Portlets support persistent configuration and customization, profile
information....
dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
...pecially since your data are already factored, you can use complete from "tidyr" to get what you might be looking for:
library(tidyr)
df %>%
group_by(b) %>%
summarise(count_a=length(a)) %>%
complete(b)
# Source: local data frame [3 x 2]
#
# b count_a
# (fctr) (int)
# 1 ...
Why not use exceptions as regular flow of control?
To avoid all standard-answers I could have Googled on, I will provide an example you all can attack at will.
24 Answers
...
Boolean operators && and ||
...ing). For example, here's a comparison using an undefined value a; if it didn't short-circuit, as & and | don't, it would give an error.
a
# Error: object 'a' not found
TRUE || a
# [1] TRUE
FALSE && a
# [1] FALSE
TRUE | a
# Error: object 'a' not found
FALSE & a
# Error: object 'a' ...
Difference between Pragma and Cache-Control headers?
...ure, you must first check with me that it is up-to-date (i.e. perform revalidation)".
– clime
Mar 7 '13 at 14:03
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