大约有 43,000 项符合查询结果（耗时：0.0501秒） [XML]
string.Join on a List or other type
...>)
If you can't upgrade, you can achieve the same effect using Select and ToArray.
return string.Join(",", a.Select(x => x.ToString()).ToArray());
share
|
improve this answer
...
Rails: select unique values from a column
...ing)
Result of this is a collection of Model objects. Not plain ratings. And from uniq's point of view, they are completely different. You can use this:
Model.select(:rating).map(&:rating).uniq
or this (most efficient)
Model.uniq.pluck(:rating)
# rails 5+
Model.distinct.pluck(:rating)
U...
How do you stop Console from popping up automatically in Eclipse
...e popup every few seconds. How do I stop it from automatically popping up and taking focus?
3 Answers
...
Force HTML5 youtube video
... reports are biased. Nobody said if he/she is in "html5 beta of youtube" and this is probably key factor. When I leave the html5 beta, it seems that ?html5=1 don't do anything. Every video goes with flash.
– Paul Brewczynski
Jul 13 '13 at 21:57
...
Can you make valid Makefiles without tab characters?
...that Makefiles have a tab character preceding the the content of each command line, or it throws a syntax error.
10 Answe...
How to reverse a 'rails generate'
I want to delete all the files it created and roll back any changes made, but not necessarily to the database, but more to the config files.
...
Setting table column width
...group>
<!-- Put <thead>, <tbody>, and <tr>'s here! -->
<tbody>
<tr>
<td style="background-color: #777">15%</td>
<td style="background-color: #aaa">70%</td>
<t...
std::shared_ptr of this
...is std::enable_shared_from_this just for this purpose. You inherit from it and you can call .shared_from_this() from inside the class. Also, you are creating circular dependencies here that can lead to resource leaks. That can be resolved with the use of std::weak_ptr. So your code might look like t...
How to activate virtualenv?
I have been through search and tried various alternatives without success and spent several days on it now - driving me mad.
...
How to get the index of an item in a list in a single step?
...
EDIT: If you're only using a List<> and you only need the index, then List.FindIndex is indeed the best approach. I'll leave this answer here for those who need anything different (e.g. on top of any IEnumerable<>).
Use the overload of Select which takes...