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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...
Placeholder in UITextView
...want the UITextView to have a placeholder similar to the one you can set for an UITextField .
62 Answers
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What is the most efficient string concatenation method in python?
...robably fast enough and has the benefit of being idiomatic and thus easier for other python programmers to understand.
Finally, the golden rule of optimization: don't optimize unless you know you need to, and measure rather than guessing.
You can measure different methods using the timeit module. ...
How to dynamically load a Python class
...:
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...
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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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...
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 do I create a constant in Python?
...n answer, far below, with a short and simple implementation of "Constants" for python 2.7 (which lacks "enum"). These are enum-like read-only name.attribute, and can contain any value. Declaration is easy Nums = Constants(ONE=1, PI=3.14159, DefaultWidth=100.0), Usage is straightforward print 10 + Nu...
MongoDB数据导出导入工具：mongoexport,mongoimport - 大数据 & AI - 清泛...
...ssage
-v [ --verbose ] be more verbose (include multiple times for more
verbosity e.g. -vvvvv)
--version print the program's version and exit
-h [ --host ] arg mongo host to connect to ( <set name>/s1,s2 for sets)
--port arg ...