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How to calculate an angle from three points? [closed]
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Only a handful of languages use a caret for 'power of', so if you don't want to call it arcos, please just type cos⁻¹. (If you're using a commercial operating system that makes it difficult to type exponents, I expect there would ...
Python argparse mutual exclusive group
...ns within the group mutually exclusive.
What you're looking for is subcommands. Instead of prog [ -a xxxx | [-b yyy -c zzz]], you'd have:
prog
command 1
-a: ...
command 2
-b: ...
-c: ...
To invoke with the first set of arguments:
prog command_1 -a xxxx
To invoke with the sec...
How can I run dos2unix on an entire directory? [closed]
...args -0 dos2unix
Will recursively find all files inside current directory and call for these files dos2unix command
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Minimal web server using netcat
.../1.1 200 OK\n\n $(date)"'; done
The -cmakes netcat execute the given command in a shell, so you can use echo. If you don't need echo, use -e. For further information on this, try man nc. Note, that when using echo there is no way for your program (the date-replacement) to get the browser request. ...
Detect URLs in text with JavaScript
...ou need a good regex that matches urls. This is hard to do. See here, here and here:
...almost anything is a valid URL. There
are some punctuation rules for
splitting it up. Absent any
punctuation, you still have a valid
URL.
Check the RFC carefully and see if you
can construct ...
What is a mixin, and why are they useful?
...ming Python ", Mark Lutz mentions "mixins". I'm from a C/C++/C# background and I have not heard the term before. What is a mixin?
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PSQLException: current transaction is aborted, commands ignored until end of transaction block
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I got this error using Java and PostgreSQL doing an insert on a table. I will illustrate how you can reproduce this error:
org.postgresql.util.PSQLException: ERROR:
current transaction is aborted, commands ignored until end of transaction block
Summa...
What is memoization and how can I use it in Python?
I just started Python and I've got no idea what memoization is and how to use it. Also, may I have a simplified example?
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How do I move an existing Git submodule within a Git repository?
...ules:
Since git 1.8.5, git mv old/submod new/submod works as expected and does all the plumbing for you. You might want to use git 1.9.3 or newer, because it includes fixes for submodule moving.
The process is similar to how you'd remove a submodule (see How do I remove a submodule?):
Edi...
Why isn't sizeof for a struct equal to the sum of sizeof of each member?
...y alignment constraints. Data structure alignment impacts both performance and correctness of programs:
Mis-aligned access might be a hard error (often SIGBUS).
Mis-aligned access might be a soft error.
Either corrected in hardware, for a modest performance-degradation.
Or corrected by emulation...