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How do I append one string to another in Python?
...ference to a string and you concatenate another string to the end, CPython now special cases this and tries to extend the string in place.
The end result is that the operation is amortized O(n).
e.g.
s = ""
for i in range(n):
s+=str(i)
used to be O(n^2), but now it is O(n).
From the source...
How can I cast int to enum?
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@FlySwat, what if YourEnum is dynamic and will only be known at runtime, and what I want is to convert to Enum?
– Shimmy Weitzhandler
Feb 19 '12 at 9:56
235
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How to create NS_OPTIONS-style bitmask enumerations in Swift?
...tocol extensions take care of most of the boilerplate for these, which are now imported as a struct that conforms to OptionSetType. (RawOptionSetType has disappeared as of Swift 2 beta 2.) The declaration is far simpler:
struct MyOptions : OptionSetType {
let rawValue: Int
static let None ...
enum - getting value of enum on string conversion
...x = 1
y = 2
def __str__(self):
return '%s' % self.value
now I can just do
print(D.x) to get 1 as result.
You can also use self.name in case you wanted to print x instead of 1.
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What are some good Python ORM solutions? [closed]
...leaner syntax and is easier to write for (ActiveRecord pattern). I don't know about performance differences.
SQLAlchemy also has a declarative layer that hides some complexity and gives it a ActiveRecord-style syntax more similar to the Django ORM.
I wouldn't worry about Django being "too heavy."...
What is the __del__ method, How to call it?
...lace where this method is used. The main reason for that is that I do not know how this method is used, probably not like that: obj1.del() . So, my questions is how to call the __del__ method?
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How to find the installed pandas version
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Disregard. Had to restart kernel. Now both match.
– ericOnline
May 12 at 19:22
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Efficient evaluation of a function at every cell of a NumPy array
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@Peter: Ah, now I see that you have mentioned assigning the result back to the former array in your original question. I'm sorry I missed that when first reading it. Yeah, in that case the double loop must be faster. But have you also tr...
How to reliably open a file in the same directory as a Python script
...test.py"
sys.argv[0]: C:\Documents and Settings\Admin\test.py
Ok so know you can get the file name, great big deal, now to get the application directory you can know use os.path, specifically abspath and dirname
import sys, os
print os.path.dirname(os.path.abspath(sys.argv[0]))
That...
Performance of Find() vs. FirstOrDefault() [duplicate]
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It's now 100% obvious what is the only difference between them, I was hoping to see something else, like more tricky to identify. It's always interesting to see what's going on under the hood of .net framework. thanks!
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