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Using Linq to get the last N elements of a collection?
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This approach preserves item order without a dependency on any sorting, and has broad compatibility across several LINQ providers.
It is important to take care not to call Skip with a negative number. Some providers, such as the Entity Framework, will produce an ArgumentException when presented ...
What is the difference between UTF-8 and ISO-8859-1?
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I had seen where Umlaut's are not supposedly converted with UTF8. We saw examples of this and in searching we found the ISO-8859-1 and it seems to work. We have a lot of German Scientist we work with.
– Aggie Jon of 87
Jul 25 '18...
Create batches in linq
...ches as entire collections of items (which accumulates the items anyways), and often process batches in parallel (which is not supported by the iterator approach, and will be a nasty surprise unless you know the implementation details).
– Michael Petito
May 19 ...
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...
Placing/Overlapping(z-index) a view above another view in android
I have a linear layout which consists of imageview and textview , one below another in a linear layout.
11 Answers
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How can I hash a password in Java?
... good algorithm to use for password hashing.
byte[] salt = new byte[16];
random.nextBytes(salt);
KeySpec spec = new PBEKeySpec("password".toCharArray(), salt, 65536, 128);
SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
byte[] hash = f.generateSecret(spec).getEncoded();
Bas...
How do I concatenate two strings in C?
...e that the function returns a block of heap allocated memory to the caller and passes on ownership of that memory. It is the responsibility of the caller to free the memory when it is no longer needed.
Call the function like this:
char* s = concat("derp", "herp");
// do things with s
free(s); // d...
Kill child process when parent process is killed
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From this forum, credit to 'Josh'.
Application.Quit() and Process.Kill() are possible solutions, but have proven to be unreliable. When your main application dies, you are still left with child processes running. What we really want is for the child processes to die as soon as t...
Drop data frame columns by name
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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
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Picking a random element from a set
How do I pick a random element from a set?
I'm particularly interested in picking a random element from a
HashSet or a LinkedHashSet, in Java.
Solutions for other languages are also welcome.
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