大约有 42,000 项符合查询结果（耗时：0.0329秒） [XML]
Change the color of glyphicons to blue in some- but not at all places using Bootstrap 2
...
answered Aug 20 '13 at 12:32
Vikas GhodkeVikas Ghodke
6,29855 gold badges2323 silver badges3737 bronze badges
...
Determine device (iPhone, iPod Touch) with iOS
...
31 Answers
31
Active
...
How to find list intersection?
actual output: [1,3,5,6]
expected output: [1,3,5]
11 Answers
11
...
Are list-comprehensions and functional functions faster than “for loops”?
...in range(10)]`>)
1 0 BUILD_LIST 0
3 LOAD_FAST 0 (.0)
>> 6 FOR_ITER 12 (to 21)
9 STORE_FAST 1 (x)
12 LOAD_FAST 1 (x)
15 LIST_APPEND 2
...
How to add a new row to an empty numpy array
...
237
The way to "start" the array that you want is:
arr = np.empty((0,3), int)
Which is an empty ...
dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
....drop argument that does just what you asked for:
df = data.frame(a=rep(1:3,4), b=rep(1:2,6))
df$b = factor(df$b, levels=1:3)
df %>%
group_by(b, .drop=FALSE) %>%
summarise(count_a=length(a))
#> # A tibble: 3 x 2
#> b count_a
#> <fct> <int>
#> 1 1 ...
How to convert a data frame column to numeric type?
...ac num
1 a 1 1 a 1
2 b 2 2 b 2
3 c 3 3 c 3
4 d 4 4 d 4
5 e 5 5 e 5
and let us run:
> sapply(d, mode)
char fake_char fac char_fac num
"character" "character...
Is there a better way to iterate over two lists, getting one element from each list for each iterati
...
answered Dec 17 '09 at 2:03
Roberto BonvalletRoberto Bonvallet
25.9k55 gold badges3737 silver badges5555 bronze badges
...
What is the difference between Python's list methods append and extend?
...
5329
append: Appends object at the end.
x = [1, 2, 3]
x.append([4, 5])
print (x)
gives you: [1, ...