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What algorithms compute directions from point A to point B on a map?
...oughly half the work (2*pi*(r/2)^2 vs pi*r^2).
To avoid exploring the back-alleys of every city between your source and destination, you can have several layers of map data: A 'highways' layer that contains only highways, a 'secondary' layer that contains only secondary streets, and so forth. Then, ...
SQLAlchemy: Creating vs. Reusing a Session
Just a quick question: SQLAlchemy talks about calling sessionmaker() once but calling the resulting Session() class each time you need to talk to your DB. For me that means the second I would do my first session.add(x) or something similar, I would first do
...
What is the difference between Tomcat, JBoss and Glassfish?
... and CORBA. We didn't include these in the Java EE version of Tomcat, but all current technology is there like JAX-RS, JAX-WS, JMS, CDI, JPA, JSF, EJB, JTA, etc.
– David Blevins
Aug 26 '13 at 21:01
...
On logout, clear Activity history stack, preventing “back” button from opening logged-in-only Activi
All activities in my application require a user to be logged-in to view. Users can log out from almost any activity. This is a requirement of the application. At any point if the user logs-out, I want to send the user to the Login Activity . At this point I want this activity to be at the bottom of...
How to concatenate strings of a string field in a PostgreSQL 'group by' query?
...xt) (
SFUNC=string_agg_transfn,
STYPE=text
);
Custom variations (all Postgres versions)
Prior to 9.0, there was no built-in aggregate function to concatenate strings. The simplest custom implementation (suggested by Vajda Gabo in this mailing list post, among many others) is to use the bu...
Removing duplicate rows in Notepad++
...d to sort by line, and remove the duplicate lines at the same time.
To install the TextFX in the latest release of Notepad++ you need to download it from here: https://sourceforge.net/projects/npp-plugins/files/TextFX
The TextFX plugin used to be included in older versions of Notepad++, or be possib...
Split string into an array in Bash
...;<< "$string"
Note that the characters in $IFS are treated individually as separators so that in this case fields may be separated by either a comma or a space rather than the sequence of the two characters. Interestingly though, empty fields aren't created when comma-space appears in the in...
Moving Files into a Real Folder in Xcode
...proach for 2017 (Xcode 6, 7, 8, and sometimes 9, since it does it automagically some of the time):
If you're moving a bunch of files into a new folder and are keeping the child hierarchy, it's actually a lot easier than moving each file individually:
Create new groups in the Xcode folder tree and...
Do threads have a distinct heap?
...
No. All threads share a common heap.
Each thread has a private stack, which it can quickly add and remove items from. This makes stack based memory fast, but if you use too much stack memory, as occurs in infinite recursion, yo...
Get the subdomain from a URL
...
Anyone have any great ideas besides
storing a list of all TLDs?
No, because each TLD differs on what counts as a subdomain, second level domain, etc.
Keep in mind that there are top level domains, second level domains, and subdomains. Technically speaking, everything except ...