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Best practice for creating millions of small temporary objects
...d them instead of creating new instances. The same for, for example, empty strings.
Another source was multiple booleans which were replaced with one int and for each boolean we use just one byte of the int.
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How do I cast a variable in Scala?
...sult of this pattern matching cast into a variable? like in java if it was String a = (String) b; what would the scala equivalent be?
– James McMahon
Jul 19 '12 at 3:58
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What are naming conventions for MongoDB?
...o name a collection few precautions to be taken :
A collection with empty string (“”) is not a valid collection name.
A collection name should not contain the null character because this defines the end of collection name.
Collection name should not start with the prefix “system.” as this i...
How to check that an element is in a std::set?
...lly get std::set::contains method.
#include <iostream>
#include <string>
#include <set>
int main()
{
std::set<std::string> example = {"Do", "not", "panic", "!!!"};
if(example.contains("panic")) {
std::cout << "Found\n";
} else {
std::cout ...
regex for zip-code
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^\d{5}(?:[-\s]\d{4})?$
^ = Start of the string.
\d{5} = Match 5 digits (for condition 1, 2, 3)
(?:…) = Grouping
[-\s] = Match a space (for condition 3) or a hyphen (for condition 2)
\d{4} = Match 4 digits (for condition 2, 3)
…? = The pattern before it is optio...
How to break out or exit a method in Java?
....g
import java.util.Scanner;
class demo
{
public static void main(String args[])
{
outerLoop://Label
for(int i=1;i<=10;i++)
{
for(int j=1;j<=i;j++)
{
for(int k=1;k<=j;k++)
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Is there StartsWith or Contains in t sql with variables?
...'prefix%' will be very fast when colName is indexed, but colName LIKE '%substring%' or colName LIKE '%suffix' will be slow because SQL Server does not create suffix-trees when indexing text. Similarly using LEFT with a column will also be slow because those queries are not SARGable. SARGability is i...
Running bash script from within python
...eep.sh', 0o755) then you could read the script as a text file and pass the string to subprocess module instead:
with open('sleep.sh', 'rb') as file:
script = file.read()
rc = call(script, shell=True)
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In-place edits with sed on OS X
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You can use:
sed -i -e 's/<string-to-find>/<string-to-replace>/' <your-file-path>
Example:
sed -i -e 's/Hello/Bye/' file.txt
This works flawless in Mac.
sha...
Const in JavaScript: when to use it and is it necessary?
... You should say that this "immutable" behaviour is only applicable to Strings, Basic Types. Using Objects, Arrays etc. it is possible to change the values but it is not possible to re-assign an new "Object", e.g. const a = ["a","b"]; a = []; will throw an error otherwise it is possible
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