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How can I quickly sum all numbers in a file?
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For a Perl one-liner, it's basically the same thing as the awk solution in Ayman Hourieh's answer:
% perl -nle '$sum += $_ } END { print $sum'
If you're curious what Perl one-liners do, you can deparse them:
% perl -MO=Deparse -nle '$sum += $_ } END ...
In Python script, how do I set PYTHONPATH?
... that if you want to make sure that Python checks the new directory before all of the others when importing, you should put the new directory first in the list, as in sys.path.insert(0, '/path/to/whatever').
– wecsam
Jun 15 '17 at 16:22
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What is mattr_accessor in a Rails module?
I couldn't really find this in Rails documentation but it seems like 'mattr_accessor' is the Module corollary for 'attr_accessor' (getter & setter) in a normal Ruby class .
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CMake unable to determine linker language with C++
...d (according to the documentation), but it wasn't helpful to me:
Optionally you can specify which languages your project supports.
Example languages are CXX (i.e. C++), C, Fortran, etc. By default C
and CXX are enabled. E.g. if you do not have a C++ compiler, you can
disable the check for ...
Is there any pythonic way to combine two dicts (adding values for keys that appear in both)?
...t;> A + B
Counter({'c': 7, 'b': 5, 'd': 5, 'a': 1})
Counters are basically a subclass of dict, so you can still do everything else with them you'd normally do with that type, such as iterate over their keys and values.
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Why use Ruby's attr_accessor, attr_reader and attr_writer?
...write classes which will work correctly no matter how their public API is called.
class Person
attr_accessor :age
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end
Here, I can see that I may both read and write the age.
class Person
attr_reader :age
...
end
Here, I can see that I may only read the age. Imagine that it is set ...
Best way to select random rows PostgreSQL
...lass WHERE oid = 'schema_name.big'::regclass;
As long as ct isn't much smaller than id_span, the query will outperform other approaches.
WITH params AS (
SELECT 1 AS min_id -- minimum id <= current min id
, 5100000 AS id_span -- rounded up. (max_id - m...
ValidateAntiForgeryToken purpose, explanation and example
...icking the logged in user into submitting a form, or by simply programmatically triggering a form when the page loads.
The feature doesn't prevent any other type of data forgery or tampering based attacks.
To use it, decorate the action method or controller with the ValidateAntiForgeryToken attrib...
Is gettimeofday() guaranteed to be of microsecond resolution?
I am porting a game, that was originally written for the Win32 API, to Linux (well, porting the OS X port of the Win32 port to Linux).
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Mercurial .hgignore for Visual Studio 2010 projects
...ut an entry that's already there.. Feel free to edit the list and yes I totally agree, it should be added
– Shady M. Najib
Apr 14 '11 at 12:07
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