大约有 23,000 项符合查询结果（耗时：0.0502秒） [XML]
Simultaneously merge multiple data.frames in a list
...using the tidyverse packages. For comparison purposes below, you'll find a base R version using the same sample dataset.
1) Join them with reduce from the purrr package:
The purrr package provides a reduce function which has a concise syntax:
library(tidyverse)
list(x, y, z) %>% reduce(left_...
The type must be a reference type in order to use it as parameter 'T' in the generic type or method
...or sure without a repro example):
public class Derived<SomeModel> : Base<SomeModel> where SomeModel : class, IModel
^^^^^
see this bit
...
Break promise chain and call a function based on the step in the chain where it is broken (rejected)
...then(stepTwo).then(null, handleErrorOne)
Angular's promise library $q is based on kriskowal's Q library (which has a richer API, but contains everything you can find in $q). Q's API docs on GitHub could prove useful. Q implements the Promises/A+ spec, which goes into detail on how then and the pro...
When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used?
...inheritance hierarchies. It is unnecessary when casting upwards (towards a base class), but when casting downwards it can be used as long as it doesn't cast through virtual inheritance. It does not do checking, however, and it is undefined behavior to static_cast down a hierarchy to a type that isn'...
ObservableCollection not noticing when Item in it changes (even with INotifyPropertyChanged)
...llectionChanged event firing.
public class CollectionViewModel : ViewModelBase
{
public ObservableCollection<EntityViewModel> ContentList
{
get { return _contentList; }
}
public CollectionViewModel()
{
_contentList = new ObservableCollection<...
Jquery insert new row into table at a certain index
...$('#my_table > tbody > tr').eq(i-1).after(html);
The indexes are 0 based, so to be the 4th row, you need i-1, since .eq(3) would be the 4th row, you need to go back to the 3rd row (2) and insert .after() that.
share
...
Rename multiple files based on pattern in Unix
There are multiple files in a directory that begin with prefix fgh , for example:
22 Answers
...
Fast and responsive interactive charts/graphs: SVG, Canvas, other?
...vis version has to recalculate all attributes on all elements.) The Canvas-based semantic zooming is a bit more zippy than SVG, but SVG semantic zooming still feels responsive.
Yet there is no magic bullet for performance, and these four possible approaches don't begin to cover the full space of po...
Traits vs. interfaces
...works great. But maybe a few weeks later you decide you want to use a file-based cache system instead of APC. Now you have to change your controller code because you've programmed your controller to work with the functionality of the ApcCacher class rather than to an interface that expresses the cap...
Underscore: sortBy() based on multiple attributes
I am trying to sort an array with objects based on multiple attributes. I.e if the first attribute is the same between two objects a second attribute should be used to comapare the two objects. For example, consider the following array:
...