大约有 41,000 项符合查询结果（耗时：0.0789秒） [XML]
What does the KEY keyword mean?
...
|
edited Sep 4 '19 at 15:19
Yves M.
24.5k1919 gold badges8989 silver badges118118 bronze badges
...
Reorder levels of a factor without changing order of values
...
Use the levels argument of factor:
df <- data.frame(f = 1:4, g = letters[1:4])
df
# f g
# 1 1 a
# 2 2 b
# 3 3 c
# 4 4 d
levels(df$g)
# [1] "a" "b" "c" "d"
df$g <- factor(df$g, levels = letters[4:1])
# levels(df$g)
# [1] "d" "c" "b" "a"
df
# f g
# 1 1 a
# 2 2 b
# 3 3 c
# 4 ...
How to get execution time in rails console?
...
242
timing = Benchmark.measure { Post.all }
The various attributes of the object returned (Benchm...
Converting of Uri to String
...
answered Jun 28 '13 at 2:49
Rico HarisinRico Harisin
3,02911 gold badge1111 silver badges77 bronze badges
...
What is the way to quick-switch between tabs in Xcode 4
I have opened many tabs while working on project. (new feature in Xcode 4).
5 Answers
...
Difference between java.exe and javaw.exe
...
4 Answers
4
Active
...
How can I join multiple SQL tables using the IDs?
I have 4 different tables that I want to join. The tables are structured with columns as follows:
4 Answers
...
Trying to load jquery into tampermonkey script
... load jQuery. Something like:
// @require http://code.jquery.com/jquery-3.4.1.min.js
(Selecting your desired version from the of list of available versions of jQuery)
share
|
improve this answer
...