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Time complexity of Sieve of Eratosthenes algorithm
...oose upper-bound is n(1+1/2+1/3+1/4+1/5+1/6+…1/n) (sum of reciprocals of all numbers up to n), which is O(n log n): see Harmonic number. A more proper upper-bound is n(1/2 + 1/3 + 1/5 + 1/7 + …), that is sum of reciprocals of primes up to n, which is O(n log log n). (See here or here.)
The "find...
How to know/change current directory in Python shell?
...now how to change.
edit
Under Windows:
set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib
(taken from http://docs.python.org/using/windows.html)
edit 2
... and even better: use virtualenv and virtualenv_wrapper, this will allow you to create a development environment where you can add module paths ...
How do you reference a capture group with regex find and replace in Visual Studio 2012, 2013, 2015,
...gular expressions' is checked, and put the following as the text to find:
_platformActions.InstallApp\((.+)\)
And the following as the text to replace it with:
this.Platform().App($1).Install()
Note: As SLaks points out in a comment below, the change in regex syntax is due to VS2012 switching to...
Array.push() if does not exist?
... it doesn't then just push the item into the array:
var newItem = "NEW_ITEM_TO_ARRAY";
var array = ["OLD_ITEM_1", "OLD_ITEM_2"];
array.indexOf(newItem) === -1 ? array.push(newItem) : console.log("This item already exists");
console.log(array)
...
How to do URL decoding in Java?
... {
String result = java.net.URLDecoder.decode(url, StandardCharsets.UTF_8.name());
} catch (UnsupportedEncodingException e) {
// not going to happen - value came from JDK's own StandardCharsets
}
Java 10 added direct support for Charset to the API, meaning there's no need to catch Unsuppor...
What does ':' (colon) do in JavaScript?
...
var o = {
r: 'some value',
t: 'some other value'
};
is functionally equivalent to
var o = new Object();
o.r = 'some value';
o.t = 'some other value';
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...
Multiline TextView in Android?
...
If the text you're putting in the TextView is short, it will not automatically expand to four lines. If you want the TextView to always have four lines regardless of the length of the text in it, set the android:lines attribute:
<TextView
android:id="@+id/address1"
android:gravity="left...
Can I create a One-Time-Use Function in a Script or Stored Procedure?
...nderstand the security implications before you consider this.
DECLARE @add_a_b_func nvarchar(4000) = N'SELECT @c = @a + @b;';
DECLARE @add_a_b_parm nvarchar(500) = N'@a int, @b int, @c int OUTPUT';
DECLARE @result int;
EXEC sp_executesql @add_a_b_func, @add_a_b_parm, 2, 3, @c = @result OUTPUT;
PRI...
Check if SQL Connection is Open or Closed
... as an enum and not turn it into a string.....
– marc_s
Aug 4 '11 at 15:19
4
Should've added usin...
Iterate over a list of files with spaces
...
Seems like pointing out the obvious, but in nearly all simple cases, -exec is going to be cleaner than an explicit loop: find . -iname "foo*" -exec echo "File found: {}" \;. Plus, in many cases you can replace that last \; with+ to put lots of files in the one command.
...