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What does $_ mean in PowerShell?
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This is the variable for the current value in the pipe line, which is called $PSItem in Powershell 3 and newer.
1,2,3 | %{ write-host $_ }
or
1,2,3 | %{ write-host $PSItem }
For example in the above code the %{} block is called for every value in the array. The $_ or $PSItem variable ...
Count character occurrences in a string in C++
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Small note, but the return type is typically signed. For some reason std::count returns type iterator_traits<InputIt>::difference_type, which for most standard containers is std::ptrdiff_t, not std::size_t.
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How to list all installed packages and their versions in Python?
Is there a way in Python to list all installed packages and their versions?
11 Answers
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Fatal error: Maximum execution time of 300 seconds exceeded
... This line of code will drop the max execution time restriction of a code, allowing a php code to run forever (theoretically).
– Technotronic
May 20 '15 at 13:09
2
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How to make an immutable object in Python?
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Can you use namedtuple internally inside the class instead of instantiating the object externally? I'm very new to python but the advantage to your other answer is that I can have a class hide the details and also have the power of things like optional p...
What is the difference between _tmain() and main() in C++?
...Now, in UTF-16, the character set used by Windows when Unicode is enabled, all the ASCII characters are represented as the pair of bytes \0 followed by the ASCII value.
And since the x86 CPU is little-endian, the order of these bytes are swapped, so that the ASCII value comes first, then followed b...
Best way to do multiple constructors in PHP
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<?php
class Student
{
public function __construct() {
// allocate your stuff
}
public static function withID( $id ) {
$instance = new self();
$instance->loadByID( $id );
return $instance;
}
public static function withRow( array $row ) {
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Elastic Search: how to see the indexed data
...lore your ElasticSearch cluster is to use elasticsearch-head.
You can install it by doing:
cd elasticsearch/
./bin/plugin -install mobz/elasticsearch-head
Then (assuming ElasticSearch is already running on your local machine), open a browser window to:
http://localhost:9200/_plugin/head/
Alte...
Reimport a module in python while interactive
... Redefinitions of names will override the old definitions, so this is generally not a problem, but if the new version of a module does not define a name that was defined by the old version, the old definition is not removed.
If a module imports objects from another module using from ... import ..., ...
What is the most effective way for float and double comparison?
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Be extremely careful using any of the other suggestions. It all depends on context.
I have spent a long time tracing a bugs in a system that presumed a==b if |a-b|<epsilon. The underlying problems were:
The implicit presumption in an algorithm that if a==b and b==c then a==c.
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