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Installing Python 3 on RHEL
...nstall-3.4 pip
You can create your virtualenv using pyvenv:
pyvenv /tmp/foo
[EPEL] How to install Python 3.6 on CentOS 7
With CentOS7, pip3.6 is provided as a package :)
sudo yum install -y epel-release
sudo yum install -y python36 python36-pip
You can create your virtualenv using pyvenv:
...
What does denote in C# [duplicate]
...le only allows you to invoke the method with types that are classes:
void Foo<T>(T item) where T: class
{
}
The following example only allows you to invoke the method with types that are Circle or inherit from it.
void Foo<T>(T item) where T: Circle
{
}
And there is new() that says...
How do you add a Dictionary of items into another Dictionary
...ith another one.
You can write an extension to do it
var dict1 = ["a" : "foo"]
var dict2 = ["b" : "bar"]
extension Dictionary {
mutating func update(other:Dictionary) {
for (key,value) in other {
self.updateValue(value, forKey:key)
}
}
}
dict1.update(dict2)
//...
Getting the array length of a 2D array in Java
...
Consider
public static void main(String[] args) {
int[][] foo = new int[][] {
new int[] { 1, 2, 3 },
new int[] { 1, 2, 3, 4},
};
System.out.println(foo.length); //2
System.out.println(foo[0].length); //3
System.out.println(foo[1].length); //4
}
Col...
Rails: What's a good way to validate links (URLs)?
...owing host
http://invalid##host.com
but it will allow
http://invalid-host.foo
that is a valid host, but not a valid domain if you consider the existing TLDs. Indeed, the solution would work if you want to validate the hostname, not the domain because the following one is a valid hostname
http://ho...
How do I revert all local changes in Git managed project to previous state?
...l
$ touch a
$ git add .
$ git commit -m"Add file a" > /dev/null
$ echo 'foo' >> a
$ git commit -a -m"Append foo to a" > /dev/null
$ for i in b c d e; do echo $i >>a; git commit -a -m"Append $i to a" ;done > /dev/null
$ git reset --hard HEAD^^ > /dev/null
$ cat a
foo
b
c
$ git...
ActiveRecord OR query
.../ActiveRecord may support this syntax natively. It would look similar to:
Foo.where(foo: 'bar').or.where(bar: 'bar')
As noted in this pull request https://github.com/rails/rails/pull/9052
For now, simply sticking with the following works great:
Foo.where('foo= ? OR bar= ?', 'bar', 'bar')
Upda...
is it possible to change values of the array when doing foreach in javascript?
...
Array: [1, 2, 3, 4]
Result: ["foo1", "foo2", "foo3", "foo4"]
Array.prototype.map() Keep original array
const originalArr = ["Iron", "Super", "Ant", "Aqua"];
const modifiedArr = originalArr.map(name => `${name}man`);
console.log( "Original: %s", or...
Hidden features of Perl?
...cessors indirectly through a variable - Perl does that too:
my $method = 'foo';
my $obj = My::Class->new();
$obj->$method( 'baz' ); # calls $obj->foo( 'baz' )
Defining methods through code - Perl allows that too:
*foo = sub { print "Hello world" };
Pervasive online documentation - Per...
Calling a JavaScript function named in a variable [duplicate]
...
If it´s in the global scope it´s better to use:
function foo()
{
alert('foo');
}
var a = 'foo';
window[a]();
than eval(). Because eval() is evaaaaaal.
Exactly like Nosredna said 40 seconds before me that is >.<
...