大约有 47,000 项符合查询结果（耗时：0.0731秒） [XML]
Does the ternary operator exist in R?
... returns the latest evaluation, if-else is equivalent to ?:.
> a <- 1
> x <- if(a==1) 1 else 2
> x
[1] 1
> x <- if(a==2) 1 else 2
> x
[1] 2
The power of R is vectorization. The vectorization of the ternary operator is ifelse:
> a <- c(1, 2, 1)
> x <- ifelse(a=...
Select multiple columns in data.table by their numeric indices
...
185
For versions of data.table >= 1.9.8, the following all just work:
library(data.table)
dt &...
How to form tuple column from two columns in Pandas
...
|
edited Nov 7 '16 at 16:58
answered Apr 17 '13 at 19:24
...
Clojure: cons (seq) vs. conj (list)
...
150
One difference is that conj accepts any number of arguments to insert into a collection, while...
How to split a string in shell and get the last field
Suppose I have the string 1:2:3:4:5 and I want to get its last field ( 5 in this case). How do I do that using Bash? I tried cut , but I don't know how to specify the last field with -f .
...
How do you split a list into evenly sized chunks?
...
1
2
3
Next
3306
...
Time complexity of Sieve of Eratosthenes algorithm
...
118
Your n/2 + n/3 + n/5 + … n/97 is not O(n), because the number of terms is not constant. [Ed...
How do I declare and initialize an array in Java?
...
For primitive types:
int[] myIntArray = new int[3];
int[] myIntArray = {1, 2, 3};
int[] myIntArray = new int[]{1, 2, 3};
// Since Java 8. Doc of IntStream: https://docs.oracle.com/javase/8/docs/api/java/util/stream/IntStream.html
int [] myIntArray = IntStream.range(0, 100).toArray(); // From 0 ...
git remove merge commit from history
...
101
Do git rebase -i <sha before the branches diverged> this will allow you to remove the me...