大约有 45,000 项符合查询结果（耗时：0.0457秒） [XML]
Fastest way to replace NAs in a large data.table
...e a large data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
...
Is R's apply family more than syntactic sugar?
...ntly different performance:
> fibo <- function(n) {
+ if ( n < 2 ) n
+ else fibo(n-1) + fibo(n-2)
+ }
> system.time(for(i in 0:26) fibo(i))
user system elapsed
7.48 0.00 7.52
> system.time(sapply(0:26, fibo))
user system elapsed
7.50 0.00 7.54
> s...
Random number from a range in a Bash Script
I need to generate a random port number between 2000-65000 from a shell script. The problem is $RANDOM is a 15-bit number, so I'm stuck!
...
Is unsigned integer subtraction defined behavior?
...t can be
represented by the resulting type.
(ISO/IEC 9899:1999 (E) §6.2.5/9)
As you can see, (unsigned)0 - (unsigned)1 equals -1 modulo UINT_MAX+1, or in other words, UINT_MAX.
Note that although it does say "A computation involving unsigned operands can never overflow", which might lead ...
How to determine day of week by passing specific date?
For Example I have the date: "23/2/2010" (23th Feb 2010). I want to pass it to a function which would return the day of week . How can I do this?
...
How to convert an enum type variable to a string?
...
1
2
Next
71
...
Scala: Nil vs List()
...intln (Nil equals List())
true
scala> System.identityHashCode(Nil)
374527572
scala> System.identityHashCode(List())
374527572
Nil is more idiomatic and can be preferred in most cases.
Questions?
share
|
...
John Carmack's Unusual Fast Inverse Square Root (Quake III)
...
answered Aug 28 '09 at 21:52
RushyoRushyo
6,85133 gold badges2929 silver badges4242 bronze badges
...
“cannot resolve symbol R” in Android Studio
...
1
2
3
4
Next
722
...