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Favorite (Clever) Defensive Programming Best Practices [closed]
...
SQL
When I have to delete data, I write
select *
--delete
From mytable
Where ...
When I run it, I will know if I forgot or botched the where clause. I have a safety. If everything is fine, I highlight everything after the '--' comment tokens, and run...
How can I see what I am about to push with git?
...etween what is on the remote and what you are about to push to the remote, select your local unpushed commit and right-click on the remote and choose "Diff this -> selected":
share
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improve thi...
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...
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.
...
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...
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...
#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_...