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Python dictionary: Get list of values for list of keys
...n list-comp:
Build list and throw exception if key not found: map(mydict.__getitem__, mykeys)
Build list with None if key not found: map(mydict.get, mykeys)
Alternatively, using operator.itemgetter can return a tuple:
from operator import itemgetter
myvalues = itemgetter(*mykeys)(mydict)
# use ...
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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What are allowed characters in cookies?
What are the allowed characters in both cookie name and value? Are they same as URL or some common subset?
13 Answers
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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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How to find memory leak in a C++ code/project?
...e software tools
1
Understand the operator basics. The C++ operator new allocates heap memory. The delete operator frees heap memory. For every new, you should use a delete so that you free the same memory you allocated:
char* str = new char [30]; // Allocate 30 bytes to house a string.
delete ...
What are dictionary view objects?
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Dictionary views are essentially 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, ...
How to use if - else structure in a batch file?
...stion about if - else structure in a batch file. Each command runs individually, but I couldn't use "if - else" blocks safely so these parts of my programme doesn't work. How can I do make these parts run? Thank you.
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Performance surprise with “as” and nullable types
...lable types, and I'm adding a section about using the "as" operator, which allows you to write:
10 Answers
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What's the difference between eval, exec, and compile?
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The short answer, or TL;DR
Basically, eval is used to evaluate a single dynamically generated Python expression, and exec is used to execute dynamically generated Python code only for its side effects.
eval and exec have these two differences:
eval accep...
What is a method that can be used to increment letters?
...ded to expand it a bit beyond the scope of the original question to potentially help people who are stumbling on this from Google.
I find that what I often want is something that will generate sequential, unique strings in a certain character set (such as only using letters), so I've updated this a...