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What are the differences between NP, NP-Complete and NP-Hard?
...njunction (ANDs) of 3-clause disjunctions (ORs), statements of the form
(x_v11 OR x_v21 OR x_v31) AND
(x_v12 OR x_v22 OR x_v32) AND
... AND
(x_v1n OR x_v2n OR x_v3n)
where each x_vij is a boolean variable or the negation of a variable from a finite predefined list (x_1, x...
Read environment variables in Node.js
...
process.env.ENV_VARIABLE
Where ENV_VARIABLE is the name of the variable you wish to access.
See Node.js docs for process.env.
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How to make a class property? [duplicate]
...re's how I would do this:
class ClassPropertyDescriptor(object):
def __init__(self, fget, fset=None):
self.fget = fget
self.fset = fset
def __get__(self, obj, klass=None):
if klass is None:
klass = type(obj)
return self.fget.__get__(obj, klass)(...
List all base classes in a hierarchy of given class?
...gt;
>>> import inspect
>>> inspect.getmro(B)
(<class '__main__.B'>, <class '__main__.A'>, <type 'object'>)
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Convert a list of data frames into one data frame
...
Use bind_rows() from the dplyr package:
bind_rows(list_of_dataframes, .id = "column_label")
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Is it possible to clone html element objects in JavaScript / JQuery?
...ipt using the cloneNode() method:
// Create a clone of element with id ddl_1:
let clone = document.querySelector('#ddl_1').cloneNode( true );
// Change the id attribute of the newly created element:
clone.setAttribute( 'id', newId );
// Append the newly created element on element p
document.quer...
How to import classes defined in __init__.py
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'lib/'s parent directory must be in sys.path.
Your 'lib/__init__.py' might look like this:
from . import settings # or just 'import settings' on old Python versions
class Helper(object):
pass
Then the following example should work:
from lib.settings import Values
from l...
What is dynamic programming? [closed]
...e only the necessary partial results along the way:
def fibonacci(n):
fi_minus_2 = 0
fi_minus_1 = 1
for i in range(2, n + 1):
fi = fi_minus_1 + fi_minus_2
fi_minus_1, fi_minus_2 = fi, fi_minus_1
return fi
How apply dynamic programming?
Find the recursion in the problem.
T...
How to make a Java Generic method static?
...'s how to explicitly invoke a static generic method using a specific type (_class_.<_generictypeparams_>_methodname_):
String[] newStrings = ArrayUtils.<String>appendToArray(strings, "another string");
This would only happen if the compiler can't determine the generic type because, e....
How to remove constraints from my MySQL table?
...has a special syntax for dropping foreign key constraints:
ALTER TABLE tbl_magazine_issue
DROP FOREIGN KEY FK_tbl_magazine_issue_mst_users
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