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Generate random numbers using C++11 random library
...lude <random>
#include <iostream>
int main() {
std::random_device rd;
std::mt19937 mt(rd());
std::uniform_real_distribution<double> dist(1.0, 10.0);
for (int i=0; i<16; ++i)
std::cout << dist(mt) << "\n";
}
We use random_device once to see...
Fastest method to replace all instances of a character in a string [duplicate]
...
You can use the following:
newStr = str.replace(/[^a-z0-9]/gi, '_');
or
newStr = str.replace(/[^a-zA-Z0-9]/g, '_');
This is going to replace all the character that are not letter or numbers to ('_'). Simple change the underscore value for whatever you want to replace it.
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Group by multiple columns in dplyr, using string vector input
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Since this question was posted, dplyr added scoped versions of group_by (documentation here). This lets you use the same functions you would use with select, like so:
data = data.frame(
asihckhdoydkhxiydfgfTgdsx = sample(LETTERS[1:3], 100, replace=TRUE),
a30mvxigxkghc5cdsvxvyv0ja = s...
Why use HttpClient for Synchronous Connection
...his is how I managed to make it work:
private static readonly TaskFactory _myTaskFactory = new TaskFactory(CancellationToken.None, TaskCreationOptions.None, TaskContinuationOptions.None, TaskScheduler.Default);
public static T RunSync<T>(Func<Task<T>> func)
{
...
Email validation using jQuery
...javascript for that:
function isEmail(email) {
var regex = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/;
return regex.test(email);
}
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List of foreign keys and the tables they reference
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The referenced primary key is described in the columns r_owner and r_constraint_name of the table ALL_CONSTRAINTS. This will give you the info you want:
SELECT a.table_name, a.column_name, a.constraint_name, c.owner,
-- referenced pk
c.r_owner, c_pk.table_name r_ta...
How to solve Operator '!=' cannot be applied to operands of type 'T' and 'T' [duplicate]
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public class Test<T>
{
public T Value
{
get => _Value;
set
{
// operator== is undefined for generic T; EqualityComparer solves this
if (!EqualityComparer<T>.Default.Equals(_Value, value))
{
_Valu...
How do I get class name in PHP?
...j->getNameOfClass();
?>
For older versions of PHP, you can use get_class().
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How can I apply a function to every row/column of a matrix in MATLAB?
...A = [1 2 3;
4 5 6;
7 8 9]
B = [0 1 2]
You want a function power_by_col which returns in a vector C all the elements in A to the power of the corresponding column of B.
From the above example, C is a 3x3 matrix:
C = [1^0 2^1 3^2;
4^0 5^1 6^2;
7^0 8^1 9^2]
i.e.,
C = [1 2 9;
...
How to migrate back from initial migration in Django 1.7?
...ocs.djangoproject.com/en/1.7/ref/django-admin/…
– n__o
Jul 31 '15 at 5:50
@n__o Thanks. Updated answer.
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