大约有 47,000 项符合查询结果（耗时：0.0629秒） [XML]
Applying a function to every row of a table using dplyr?
...
202
As of dplyr 0.2 (I think) rowwise() is implemented, so the answer to this problem becomes:
iri...
How do you detect Credit card type based on number?
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+50
The credit/debit card number is referred to as a PAN, or Primary Account Number. The first six digits of the PAN are taken from the I...
Shortest distance between a point and a line segment
...at l2 = length_squared(v, w); // i.e. |w-v|^2 - avoid a sqrt
if (l2 == 0.0) return distance(p, v); // v == w case
// Consider the line extending the segment, parameterized as v + t (w - v).
// We find projection of point p onto the line.
// It falls where t = [(p-v) . (w-v)] / |w-v|^2
...
How to replace NaN values by Zeroes in a column of a Pandas Dataframe?
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807
I believe DataFrame.fillna() will do this for you.
Link to Docs for a dataframe and for a Seri...
How do you round a floating point number in Perl?
... and floor()?
Trig functions?
Remember that int() merely truncates toward 0. For rounding to a certain number of digits, sprintf() or printf() is usually the easiest
route.
printf("%.3f", 3.1415926535); # prints 3.142
The POSIX module (part of the standard Perl distribution) implement...
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 ...
Tricky Google interview question
... implementation of Dijkstra’s solution.
int main()
{
const int n = 20; // Generate the first n numbers
std::vector<int> v(n);
v[0] = 1;
int i2 = 0; // Index for 2
int i5 = 0; // Index for 5
int x2 = 2 * v[i2]; // Next two candidat...
Why does the expression 0 < 0 == 0 return False in Python?
... make range comparisons easy to express. It's much nicer to be able to say 0 < x <= 5 than to say (0 < x) and (x <= 5).
These are called chained comparisons. And that's a link to the documentation for them.
With the other cases you talk about, the parenthesis force one relational opera...
How can I repeat a character in Bash?
...
410
You can use:
printf '=%.0s' {1..100}
How this works:
Bash expands {1..100} so the command be...
Get Slightly Lighter and Darker Color from UIColor
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280
- (UIColor *)lighterColorForColor:(UIColor *)c
{
CGFloat r, g, b, a;
if ([c getRed:&...