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Practical uses of different data structures [closed]
...ght accent at all. You need to understand not just which data structure to select, but some other points to consider when people think about data structures:
pros and cons of the common data structures
why each data structure exist
how it actually work in the memory
specific questions/exe...
How to change the order of DataFrame columns?
...mean(1))
http://pandas.pydata.org/pandas-docs/stable/dsintro.html#column-selection-addition-deletion
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Type definition in object literal in TypeScript
...ally need a type that you can be lazily initialized: Mark it is a nullable union type (null or Type). The type system will prevent you from using it without first ensuring it has a value.
In tsconfig.json, make sure you enable strict null checks:
"strictNullChecks": true
Then use this pattern an...
sql primary key and index
...dex
ON MyTable(ID)
INCLUDE (Name, Address)
So, when you use this query:
SELECT ID, Name, Address FROM MyTable WHERE ID > 1000
SQL Server will give you the result only using the index you've created and it'll not read anything from the actual table.
...
Export database schema into SQL file
...ht click the database you want to generate scripts for (not the table) and select tasks - generate scripts
Next, select the requested table/tables, views, stored procedures, etc (from select specific database objects)
Click advanced - select the types of data to script
Click Next and finish
MSDN...
TypeScript function overloading
... TypeScript 1.4, you can typically remove the need for an overload using a union type. The above example can be better expressed using:
myMethod(a: string | number, b?: string) {
alert(a.toString());
}
The type of a is "either string or number".
...
Why was the switch statement designed to need a break?
...
2. Antipatterns: Doesn't provide "clean" tagged unions, one of the two fundamental data-representation idioms of assembly. (Knuth, vol 1, ch 2) Instead, "untagged unions," a non-idiomatic hack. This choice has hobbled the way people think of data for decades. And NUL-termi...
What are the differences between struct and class in C++?
...ate by
default. Members of a class defined
with the keywords struct or union
are public by default.
Additional difference: the keyword class can be used to declare template parameters, while the struct keyword cannot be so used.
...
When should I use Kruskal as opposed to Prim (and vice versa)?
...c.
If you implement both Kruskal and Prim, in their optimal form : with a union find and a finbonacci heap respectively, then you will note how Kruskal is easy to implement compared to Prim.
Prim is harder with a fibonacci heap mainly because you have to maintain a book-keeping table to record the...
What are the options for storing hierarchical data in a relational database? [closed]
...lies? Perform a traversal on both sub-trees computing the intersection and union of the two sub-trees. The percent similar is the intersection divided by the union.
Transitive Closure: Walk the sub-tree and sum up the field(s) of interest, e.g. "How much aluminum is in a sub-assembly?"
Yes, you ca...