大约有 48,000 项符合查询结果（耗时：0.0574秒） [XML]
How to randomize (or permute) a dataframe rowwise and columnwise?
...,]
> df2
a b c
3 0 1 0
4 0 0 0
2 1 0 0
1 1 1 0
By default sample() randomly reorders the elements passed as the first argument. This means that the default size is the size of the passed array. Passing parameter replace=FALSE (the default) to sample(...) ensures that sampling is done withou...
What should main() return in C and C++?
...t is the correct (most efficient) way to define the main() function in C and C++ — int main() or void main() — and why? And how about the arguments?
If int main() then return 1 or return 0 ?
...
Design patterns or best practices for shell scripts [closed]
...
I wrote quite complex shell scripts and my first suggestion is "don't". The reason is that is fairly easy to make a small mistake that hinders your script, or even make it dangerous.
That said, I don't have other resources to pass you but my personal experienc...
Approximate cost to access various caches and main memory?
Can anyone give me the approximate time (in nanoseconds) to access L1, L2 and L3 caches, as well as main memory on Intel i7 processors?
...
Android requires compiler compliance level 5.0 or 6.0. Found '1.7' instead. Please use Android Tools
Did anybody have similar problem with this, I import android project and I get
errors like
12 Answers
...
What is the usefulness of PUT and DELETE HTTP request methods?
... origin server. If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI …
For the full specification visit:
http://www.w3.org/Protocols/rfc2616/rf...
What's the difference between HEAD^ and HEAD~ in Git?
...n I specify an ancestor commit object in Git, I'm confused between HEAD^ and HEAD~ .
15 Answers
...
Repeat String - Javascript
...
Note to new readers: This answer is old and and not terribly practical - it's just "clever" because it uses Array stuff to get
String things done. When I wrote "less process" I definitely meant
"less code" because, as others have noted in subsequent answers, it...
What is the difference between BIT and TINYINT in MySQL?
...NT is an 8-bit integer value, a BIT field can store between 1 bit, BIT(1), and 64 bits, BIT(64). For a boolean values, BIT(1) is pretty common.
share
|
improve this answer
|
...
Why does Date.parse give incorrect results?
...In the 5th edition spec the requirement was added to support a simplified (and slightly incorrect) ISO-8601 (also see What are valid Date Time Strings in JavaScript?). But other than that, there was no requirement for what Date.parse / new Date(string) should accept other than that they had to accep...