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Maintain/Save/Restore scroll position when returning to a ListView
... - mList.getPaddingTop());
// ...
// restore index and position
mList.setSelectionFromTop(index, top);
Explanation:
ListView.getFirstVisiblePosition() returns the top visible list item. But this item may be partially scrolled out of view, and if you want to restore the exact scroll position of t...
What is pseudopolynomial time? How does it differ from polynomial time?
...mon intuition for polynomial time is "time O(nk) for some k." For example, selection sort runs in time O(n2), which is polynomial time, while brute-force solving TSP takes time O(n · n!), which isn't polynomial time.
These runtimes all refer to some variable n that tracks the size of the input. Fo...
How to Correctly Use Lists in R?
...dresses the question of the difference between [] and [[]].
In short [[]] selects a single item from a list and [] returns a list of the selected items. In your example, x = list(1, 2, 3, 4)' item 1 is a single integer but x[[1]] returns a single 1 and x[1] returns a list with only one value.
>...
MySQL - length() vs char_length()
... in two bytes. Or UTF-8, where the number of bytes varies. For example:
select length(_utf8 '€'), char_length(_utf8 '€')
--> 3, 1
As you can see the Euro sign occupies 3 bytes (it's encoded as 0xE282AC in UTF-8) even though it's only one character.
...
Unique random string generation
...ncat(
Enumerable
.Repeat(0, int.MaxValue)
.Select(e => RandomByte())
.Where(randomByte => randomByte < outOfRange)
.Take(length)
.Select(randomByte => alphabet[randomByte % alphabet.Length])
);
}
byte RandomByte()
{...
Sqlite LIMIT / OFFSET query
...< 100000; i++)
{
//first version
timeLimitOffset += SqlDuraction("Select * from table1 order by col1 LIMIT " + (i + 1) + " OFFSET " + (1001 - i) + "");
// second version
timeLimitComma += SqlDuraction("Select * from table1 order by col1 LIMIT " + (1001 - i) + " , " + (i + 1) + "");
}...
Convert XLS to CSV on command line
...
The code converts only the active worksheet. To select another worksheet, add the following line after the oExcel.Workbooks.Open line with the desired index of the worksheet (starts at 1): oBook.Worksheets(1).Activate
– humbads
Oct 3...
Node.js Best Practice Exception Handling
...any different sources on this topic including code example and quotes from selected blog posts. The complete list of best practices can be found here
Best practices of Node.JS error handling
Number1: Use promises for async error handling
TL;DR: Handling async errors in callback style is proba...
Quick and easy file dialog in Python?
... copy/paste the path. I would like a quick and easy way to present a file selection dialog to the user, they can select the file, and then it's loaded to the database. (In my use case, if they happened to chose the wrong file, it would fail parsing, and wouldn't be a problem even if it was loaded ...
#1071 - Specified key was too long; max key length is 1000 bytes
... the best prefix length for a given column? Here's a method to find out:
SELECT
ROUND(SUM(LENGTH(`menu_link`)<10)*100/COUNT(`menu_link`),2) AS pct_length_10,
ROUND(SUM(LENGTH(`menu_link`)<20)*100/COUNT(`menu_link`),2) AS pct_length_20,
ROUND(SUM(LENGTH(`menu_link`)<50)*100/COUNT(`menu_...