大约有 46,000 项符合查询结果（耗时：0.0277秒） [XML]
Why does changing 0.1f to 0 slow down performance by 10x?
...rap and resolve them using microcode.
If you print out the numbers after 10,000 iterations, you will see that they have converged to different values depending on whether 0 or 0.1 is used.
Here's the test code compiled on x64:
int main() {
double start = omp_get_wtime();
const float x[1...
Getting the array length of a 2D array in Java
... };
System.out.println(foo.length); //2
System.out.println(foo[0].length); //3
System.out.println(foo[1].length); //4
}
Column lengths differ per row. If you're backing some data by a fixed size 2D array, then provide getters to the fixed values in a wrapper class.
...
What is a good regular expression to match a URL? [duplicate]
...you want to ensure URL starts with HTTP/HTTPS:
https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)
If you do not require HTTP protocol:
[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)
To try this out s...
How to format a number as percentage in R?
...
10 Answers
10
Active
...
How to make good reproducible pandas examples
...nd below your code with your code unindented:
In [2]: df
Out[2]:
A B
0 1 2
1 1 3
2 4 6
test pd.read_clipboard(sep='\s\s+') yourself.
* I really do mean small, the vast majority of example DataFrames could be fewer than 6 rowscitation needed, and I bet I can do it in 5 rows. Can you re...
Add column with constant value to pandas dataframe [duplicate]
...numpy.random import randint
In [9]: df = DataFrame({'a': randint(3, size=10)})
In [10]:
In [10]: df
Out[10]:
a
0 0
1 2
2 0
3 1
4 0
5 0
6 0
7 0
8 0
9 0
In [11]: s = df.a[:5]
In [12]: dfa, sa = df.align(s, axis=0)
In [13]: dfa
Out[13]:
a
0 0
1 2
2 0
3 1
4 0
5 0
6 0
7 0
8 ...
Finding current executable's path without /proc/self/exe
...ross-platform interfaces. I've seen some projects mucking around with argv[0], but it doesn't seem entirely reliable.
13 A...
Syntax for creating a two-dimensional array
...
Try the following:
int[][] multi = new int[5][10];
... which is a short hand for something like this:
int[][] multi = new int[5][];
multi[0] = new int[10];
multi[1] = new int[10];
multi[2] = new int[10];
multi[3] = new int[10];
multi[4] = new int[10];
Note that every...
Image Greyscale with CSS & re-color on mouse-over?
...
filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale"); /* Fir...
Is object empty? [duplicate]
...n-zero value
// that that property is correct.
if (obj.length > 0) return false;
if (obj.length === 0) return true;
// If it isn't an object at this point
// it is empty, but it can't be anything *but* empty
// Is it empty? Depends on your application.
if (typeof...