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Python `if x is not None` or `if not x is None`?
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There's no performance difference, as they compile to the same bytecode:
Python 2.6.2 (r262:71600, Apr 15 2009, 07:20:39)
>>> import dis
>>> def f(x):
... return x is not None
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>>> dis.dis(f)
2 0 LOAD_FAST 0 (x)
3 LOAD_CONST...
Get: TypeError: 'dict_values' object does not support indexing when using python 3.2.3 [duplicate]
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In Python 3, dict.values() (along with dict.keys() and dict.items()) returns a view, rather than a list. See the documentation here. You therefore need to wrap your call to dict.values() in a call to list like so:
v = list(d.va...
Why is parenthesis in print voluntary in Python 2.7?
In Python 2.7 both the following will do the same
4 Answers
4
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How do you read a file into a list in Python? [duplicate]
...en find the mean, standard deviation, etc. without using the easy built-in Python tools.
8 Answers
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Python's time.clock() vs. time.time() accuracy?
Which is better to use for timing in Python? time.clock() or time.time()? Which one provides more accuracy?
16 Answers
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Python, Unicode, and the Windows console
...y characters. What's the best way around this? Is there any way I can make Python automatically print a ? instead of failing in this situation?
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Python Graph Library [closed]
I'm writing a python application that will make heavy use of a graph data structure. Nothing horribly complex, but I'm thinking some sort of graph/graph-algorithms library would help me out. I've googled around, but I don't find anything that particularly leaps out at me.
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Python: List vs Dict for look up table
... true for very large sets/dicts. The worst case scenario according to wiki.python.org/moin/TimeComplexity is O(n). I guess it depends on the internal hashing implementation at what point the average time diverges from O(1) and starts converging on O(n). You can help the lookup performance by compart...
Accessing the index in 'for' loops?
...h you would normally use in languages such as C or PHP), is considered non-pythonic.
The better option is to use the built-in function enumerate(), available in both Python 2 and 3:
for idx, val in enumerate(ints):
print(idx, val)
Check out PEP 279 for more.
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Accessing class variables from a list comprehension in the class definition
... a list comprehension within the class definition? The following works in Python 2 but fails in Python 3:
5 Answers
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