大约有 48,000 项符合查询结果（耗时：0.0751秒） [XML]
Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
...avoid for large data, and why := and set() were introduced to data.table.
Now, with our copied newDT we can modify it by reference :
newDT
# a b
# [1,] 1 11
# [2,] 2 200
newDT[2, b := 400]
# a b # See FAQ 2.21 for why this prints newDT
# [1,] 1 11
# [2,] 2 400
.Internal(in...
How to get all subsets of a set? (powerset)
... to for i in range(1, 1 << x).
Returning to this years later, I'd now write it like this:
def powerset(s):
x = len(s)
masks = [1 << i for i in range(x)]
for i in range(1 << x):
yield [ss for mask, ss in zip(masks, s) if i & mask]
And then the test code...
Catch multiple exceptions in one line (except block)
I know that I can do:
5 Answers
5
...
What does [].forEach.call() do in JavaScript?
...
So how do we deal with the disparity, as Motto is clearly a talented and knowledgeable guy, and I would like to imagine that I know what I'm doing/where I'm going (now and then... ...other times it's head-first learning)?
The answer is actually quite simple, and something Uncle Bob and Sir Crockf...
How to declare a structure in a header that is to be used by multiple files in c?
...een both usages (separate names and same names), and none has drawbacks I know of, so using the same name makes reading simpler if you don't use C separate "namespaces" for structs and other symbols.
share
|
...
applicationWillEnterForeground vs. applicationDidBecomeActive, applicationWillResignActive vs. appli
...
Revise some descriptions and links, 2019 for now.
– tomjpsun
Sep 20 '19 at 2:56
add a comment
|
...
Is there a way to create your own html tag in HTML5?
...s doctypes and schemas, HTML does not become invalid if a browser doesn't know a tag or two. Think of <marquee>. This has not been in the official standard. So while using it made your HTML page "officially unapproved", it didn't break the page either.
Then there is <keygen>, which was ...
Using AES encryption in C#
...e);` . The reason for this is because in Encrypt you converted ToBase64 so now you need to ConvertFromBase64String in Decrypt, otherwise you get invalid length error.
– Euthyphro
Jan 6 '17 at 21:34
...
Ruby on Rails vs ASP.NET MVC 3 for a .NET Guy? [closed]
...
Now that ASP.NET MVC is open source, I wonder how quickly it will close the feature gap with RoR. I'm putting my money on MVC3 now that the developer community will have the ability to contribute to a product that is still su...
How to comment and uncomment blocks of code in the Office VBA Editor
...Comment Block entry onto the Menu Bar (yep! the menu bar)
Note: You should now see a new icon on the menu bar.
Make sure that the new icon is highlighted (it will have a black square around it) then
click Modify Selection button on the Customize dialog box.
An interesting menu will popup.
Under ...