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Is there an expression for an infinite generator?
... very interesting way to use iter with property of int which we many a times forget.
– Senthil Kumaran
Apr 21 '11 at 3:53
3
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'printf' vs. 'cout' in C++
..." << std::endl;
While this doesn't appear too crazy (it's just two times longer), things get more crazy when you actually format arguments, instead of just printing them. For example, printing of something like 0x0424 is just crazy. This is caused by std::cout mixing state and actual values....
How to check if variable is string with python 2 and 3 compatibility
...test like that. This is a useful technique for figuring something out one time, and based on that, setting up a function that will always be correct. Thanks for the +1.
– steveha
Jul 2 '12 at 22:16
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Finding three elements in an array whose sum is closest to a given number
...force search to find the three integers?
Yep; we can solve this in O(n2) time! First, consider that your problem P can be phrased equivalently in a slightly different way that eliminates the need for a "target value":
original problem P: Given an array A of n integers and a target value S, doe...
What's the best way to check if a file exists in C?
... There are pitfalls associated with access(). There is a TOCTOU (time of check, time of use) window of vulnerability between using access() and whatever else you do afterwards. [...to be continued...]
– Jonathan Leffler
Oct 24 '08 at 7:25
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App Inventor 2 项目合并工具 AIMerge · App Inventor 2 中文网
...Blocks for Screen1 of CountDownScreen1
Appendix B: Complete Blocks for SetTime Screen
Overview
Each developer will work on their own separate project file. These project files can be either under the same username or different usernames. There can only be one “Screen1” per project, therefore...
ToList()— does it create a new list?
...assignment like objectList[0].SimpleInt=5 would not be allowed (C# compile-time error). That is because the return value of the list indexer's get accessor is not a variable (it is a returned copy of a struct value), and therefore setting its member .SimpleInt with an assignment expression is not al...
O(nlogn) Algorithm - Find three evenly spaced ones within binary string
...riple easily, and if there are too few 1s, checking all pairs takes little time. Unfortunately, while this intuition is correct and the simple approach is better than O(n2), it is not significantly better. As in sdcvvc's answer, we can take the "Cantor-like set" of strings of length n=3k, with 1s at...
How fast is D compared to C++?
I like some features of D, but would be interested if they come with a
runtime penalty?
8 Answers
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GroupBy pandas DataFrame and select most common value
...reconstructing the groupby output. It is also faster.
# Accepted answer.
%timeit source.groupby(['Country','City']).agg(lambda x:x.value_counts().index[0])
# Proposed in this post.
%timeit source.groupby(['Country','City'])['Short name'].agg(pd.Series.mode)
5.56 ms ± 343 µs per loop (mean ± std...