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Numpy - add row to array
...e necessary after every row, it's much quicker to add rows in python, then convert to numpy. Here are timing tests using python 3.6 vs. numpy 1.14, adding 100 rows, one at a time:
import numpy as np
from time import perf_counter, sleep
def time_it():
# Compare performance of two methods for a...
How do you implement a re-try-catch?
...
You need to enclose your try-catch inside a while loop like this: -
int count = 0;
int maxTries = 3;
while(true) {
try {
// Some Code
// break out of loop, or return, on success
} catch (SomeException e) {
// handle exception
if (++count == maxTries) th...
Drop data frame columns by name
...
the subset function works better as it won't convert a data frame with one column into a vector
– mut1na
Jun 28 '13 at 9:06
3
...
KeyValuePair VS DictionaryEntry
...n Chris' example (in which we have two dictionaries containing <string, int> pairs).
Dictionary<string, int> dict = new Dictionary<string, int>();
foreach (KeyValuePair<string, int> item in dict) {
int i = item.Value;
}
Hashtable hashtable = new Hashtable();
foreach (Dict...
What is the most efficient way of finding all the factors of a number in Python?
...urn set(reduce(list.__add__,
([i, n//i] for i in range(1, int(n**0.5) + 1) if n % i == 0)))
This will return all of the factors, very quickly, of a number n.
Why square root as the upper limit?
sqrt(x) * sqrt(x) = x. So if the two factors are the same, they're both the square ro...
Are C# events synchronous?
... the order they are subscribed to the event.
I too was curious about the internal mechanism of event and its related operations. So I wrote a simple program and used ildasm to poke around its implementation.
The short answer is
there's no asynchronous operation involved in subscribing or invok...
How can I get the line number which threw exception?
...
C# one liner: int line = (new StackTrace(ex, true)).GetFrame(0).GetFileLineNumber();
– gunwin
Aug 23 '13 at 12:15
...
What is the formal difference in Scala between braces and parentheses, and when should they be used?
...t is best to concentrate on where curly braces and parenthesis can be used interchangeably: when passing parameters to method calls. You may replace parenthesis with curly braces if, and only if, the method expects a single parameter. For example:
List(1, 2, 3).reduceLeft{_ + _} // valid, single Fun...
Scala how can I count the number of occurrences in a list
...
list.groupBy(i=>i).mapValues(_.size)
gives
Map[Int, Int] = Map(1 -> 1, 2 -> 3, 7 -> 1, 3 -> 1, 4 -> 3)
Note that you can replace (i=>i) with built in identity function:
list.groupBy(identity).mapValues(_.size)
...
Single controller with multiple GET methods in ASP.NET Web API
...troller}", new { action = "Get" }, new { httpMethod = new HttpMethodConstraint(HttpMethod.Get) });
routes.MapHttpRoute("DefaultApiPost", "Api/{controller}", new {action = "Post"}, new {httpMethod = new HttpMethodConstraint(HttpMethod.Post)});
I verified this solution with the test class below. I ...