大约有 48,000 项符合查询结果（耗时：0.0486秒） [XML]
Difference between '..' (double-dot) and '…' (triple-dot) in range generation?
...
5 Answers
5
Active
...
How is “int* ptr = int()” value initialization not illegal?
...
5 Answers
5
Active
...
How do I replace NA values with zeros in an R dataframe?
...), 100, replace = TRUE), 10)
> d <- as.data.frame(m)
V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1 4 3 NA 3 7 6 6 10 6 5
2 9 8 9 5 10 NA 2 1 7 2
3 1 1 6 3 6 NA 1 4 1 6
4 NA 4 NA 7 10 2 NA 4 1 8
5 1 2 4 NA 2 6 2 6 7 4
6 NA 3 NA NA 10 2 1 10 8 4
7 ...
Sample random rows in dataframe
... X2
1 0.7091409 -1.4061361
2 -1.1334614 -0.1973846
3 2.3343391 -0.4385071
4 -0.9040278 -0.6593677
5 0.4180331 -1.2592415
6 0.7572246 -0.5463655
7 -0.8996483 0.4231117
8 -1.0356774 -0.1640883
9 -0.3983045 0.7157506
10 -0.9060305 2.3234110
Then select some rows at random:
> df[s...
Global access to Rake DSL methods is deprecated
...
5 Answers
5
Active
...
Delete element in a slice
...
flornquake
2,68011 gold badge1515 silver badges2929 bronze badges
answered Jul 29 '14 at 21:47
davedave
46.2...
Determine the data types of a data frame's columns
...is makes the example exactly reproducible
my.data <- data.frame(y=rnorm(5),
x1=c(1:5),
x2=c(TRUE, TRUE, FALSE, FALSE, FALSE),
X3=letters[1:5])
@Wilmer E Henao H's solution is very streamlined:
sapply(my.data, class)
...
Find XOR of all numbers in a given range
...
5 Answers
5
Active
...
Difference between exit(0) and exit(1) in Python
...
5 Answers
5
Active
...