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Aggregate / summarize multiple variables per group (e.g. sum, mean)
...ere is this year() function from?
You could also use the reshape2 package for this task:
require(reshape2)
df_melt <- melt(df1, id = c("date", "year", "month"))
dcast(df_melt, year + month ~ variable, sum)
# year month x1 x2
1 2000 1 -80.83405 -224.9540159
2 2000 2...
What do helper and helper_method do?
helper_method is straightforward: it makes some or all of the controller's methods available to the view.
1 Answer
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What is the cleanest way to get the progress of JQuery ajax request?
...
Something like this for $.ajax (HTML5 only though):
$.ajax({
xhr: function() {
var xhr = new window.XMLHttpRequest();
xhr.upload.addEventListener("progress", function(evt) {
if (evt.lengthComputable) {
...
What is meant by the term “hook” in programming?
...erred from the conversation that a hook is a type of function. I searched for a definition but was unable to find a good answer. Would someone be able to give me an idea of what this term generally means and perhaps a small example to illustrate the definition?
...
Creating an abstract class in Objective-C
...ract, just don't use it without subclassing it. There is no compile-time enforcement that prevents instantiation of an abstract class, however. In fact, there is nothing to stop a user from providing implementations of abstract methods via a category (i.e. at runtime). You can force a user to at lea...
Expand a div to fill the remaining width
...sy, but not at all obvious. You have to trigger something called a "block formatting context" (BFC), which interacts with floats in a specific way.
Just take that second div, remove the float, and give it overflow:hidden instead. Any overflow value other than visible makes the block it's set on b...
Configuring Vim for C++
...een source and header file: A plugin
Snippets: Snipmate or UltiSnip
Search for reference of variables, functions, classes, etc.: Cscope
Go to definition: Ctags or part of YouCompleteMe subcommands mentioned above
Refactoring tools: Refactor, lh-refactor
Useful text objects: Arg text object and Class...
SQL Server String or binary data would be truncated
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You will need to post the table definitions for the source and destination tables for us to figure out where the issue is but the bottom line is that one of your columns in the source table is bigger than your destination columns. It could be that you are changing for...
AngularJS access parent scope from child controller
...
I've just checked
$scope.$parent.someProperty
works for me.
and it will be
{{$parent.someProperty}}
for the view.
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How to sum a variable by group
...ric2, x$Metric3) ...
(embedding @thelatemail comment), aggregate has a formula interface too
aggregate(Frequency ~ Category, x, sum)
Or if you want to aggregate multiple columns, you could use the . notation (works for one column too)
aggregate(. ~ Category, x, sum)
or tapply:
tapply(x$...