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How to remove an element from a list by index
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del is overloaded. For example del a deletes the whole list
– Brian R. Bondy
Mar 9 '09 at 18:36
34
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What does [:] mean?
...f population is a list, this line will create a shallow copy of the list. For an object of type tuple or a str, it will do nothing (the line will do the same without [:]), and for a (say) NumPy array, it will create a new view to the same data.
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Circle line-segment collision detection algorithm?
...the code it seems you have assumed its 1 (so its just "removed"). Do these formulas have a name or something? Maybe I can look them up in detail on Wolfram.
– Mizipzor
Jul 6 '09 at 12:17
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Getting the class name of an instance?
... classes). Your code might use some old-style classes. The following works for both:
x.__class__.__name__
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Does Python have an ordered set?
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There is an ordered set (possible new link) recipe for this which is referred to from the Python 2 Documentation. This runs on Py2.6 or later and 3.0 or later without any modifications. The interface is almost exactly the same as a normal set, except that initialisation shoul...
How to dynamically load a Python class
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components = name.split('.')
mod = __import__(components[0])
for comp in components[1:]:
mod = getattr(mod, comp)
return mod
The reason a simple __import__ won't work is because any import of anything past the first dot in a package string is an attribute of the module yo...
How to serialize SqlAlchemy result to JSON?
...s some good automatic serialization of ORM models returned from DB to JSON format.
26 Answers
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How to check version of python modules?
... systems, you can pipe this to grep(or findstr on Windows) to find the row for the particular package you're interested in:
Linux:
$ pip freeze | grep lxml
lxml==2.3
Windows:
c:\> pip freeze | findstr lxml
lxml==2.3
For an individual module, you can try the __version__ attribute, however ther...
Short description of the scoping rules?
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Actually, a concise rule for Python Scope resolution, from Learning Python, 3rd. Ed.. (These rules are specific to variable names, not attributes. If you reference it without a period, these rules apply.)
LEGB Rule
Local — Names assigned in any ...
How to check a string for specific characters?
...e above...
s.find('$')==-1 # not found
s.find('$')!=-1 # found
And so on for other characters.
... or
pattern = re.compile(r'\d\$,')
if pattern.findall(s):
print('Found')
else
print('Not found')
... or
chars = set('0123456789$,')
if any((c in chars) for c in s):
print('Found')
els...