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What are dictionary view objects?
...sentially what their name says: views are simply like a window on the keys and values (or items) of a dictionary. Here is an excerpt from the official documentation for Python 3:
>>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, 'spam': 500}
>>> keys = dishes.keys()
>>>...
BAT file: Open new cmd window and execute a command in there
I'm trying to open a new command window in a BAT file:
8 Answers
8
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Create a dictionary with list comprehension
...
{key: value for (key, value) in iterable}
Note: this is for Python 3.x (and 2.7 upwards). Formerly in Python 2.6 and earlier, the dict built-in could receive an iterable of key/value pairs, so you can pass it a list comprehension or generator expression. For example:
dict((key, func(key)) for key...
Statistics: combinations in Python
... +1 for suggesting to write something simple, for using reduce, and for the cool demo with pascal triangle
– jon_darkstar
Nov 8 '10 at 15:32
6
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How would you implement an LRU cache in Java?
...ructures would you use? I've already implemented one using LinkedHashMap and Collections#synchronizedMap , but I'm curious if any of the new concurrent collections would be better candidates.
...
Maximum single-sell profit
... , with buyDay ≤ sellDay , such that if we bought the stock on buyDay and sold it on sellDay , we would maximize our profit.
...
How to convert an xml string to a dictionary?
...ntTree.XML(xml_string)
>>> xmldict = XmlDictConfig(root)
And then use xmldict for what it is... a dict.
'''
def __init__(self, parent_element):
if parent_element.items():
self.update(dict(parent_element.items()))
for element in parent_element:
...
Clean ways to write multiple 'for' loops
.../ ...
}
(or just:
for ( auto& elem: m ) {
}
if you have C++11.)
And if you need the three indexes during such iterations, it's
possible to create an iterator which exposes them:
class Matrix3D
{
// ...
class iterator : private std::vector<int>::iterator
{
Matri...
How to elegantly rename all keys in a hash in Ruby? [duplicate]
...
Just use mappings[k] || k instead of mappings[k] above and it will leave keys not in the mapping as is.
– Mladen Jablanović
Nov 9 '10 at 20:26
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How do I see all foreign keys to a table or column?
...HEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_TABLE_NAME = '<table>';
For a Column:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABL...