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How to efficiently build a tree from a flat structure?
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Store IDs of the objects in a hash table mapping to the specific object. Enumerate through all the objects and find their parent if it exists and update its parent pointer accordingly.
class MyObject
{ // The actual object
public int ParentID { get; set; ...
HTML colspan in CSS
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Tables are structural elements and just because using colspan changes its appearance does not mean it's not. CSS is used to style elements and not change the structure. The W3C discusses table structure here: w3.org/TR/h...
Which is more preferable to use: lambda functions or nested functions ('def')?
...with def. The difference is due to def creating a name entry in the locals table. The resulting function has the same execution speed.
Readability:
Lambda functions are somewhat less readable for most Python users, but also much more concise in some circumstances. Consider converting from using ...
How do I change column default value in PostgreSQL?
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'SET' is forgotten
ALTER TABLE ONLY users ALTER COLUMN lang SET DEFAULT 'en_GB';
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mmap() vs. reading blocks
...r random access, especially if your access patterns are sparse and unpredictable.
Memory maps allow you to keep using pages from the cache until you are done. This means that if you use a file heavily for a long period of time, then close it and reopen it, the pages will still be cached. With read...
Create table in SQLite only if it doesn't exist already
I want to create a table in a SQLite database only if doesn't exist already. Is there any way to do this? I don't want to drop the table if it exists, only create it if it doesn't.
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Zip lists in Python
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len(result[0]) wont work. 'zip' object is not subscriptable
– GilbertS
Feb 23 at 16:23
3
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How to get all Errors from ASP.Net MVC modelState?
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During debugging I find it useful to put a table at the bottom of each of my pages to show all ModelState errors.
<table class="model-state">
@foreach (var item in ViewContext.ViewData.ModelState)
{
if (item.Value.Errors.Any())
{
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How do you check “if not null” with Eloquent?
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If you wanted to use the DB facade:
DB::table('table_name')->whereNotNull('sent_at')->get();
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How to convert a table to a data frame
I have a table in R that has str() of this:
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