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Why is it slower to iterate over a small string than a small list?
...nd with timeit and noticed that doing a simple list comprehension over a small string took longer than doing the same operation on a list of small single character strings. Any explanation? It's almost 1.35 times as much time.
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How do I translate an ISO 8601 datetime string into a Python datetime object? [duplicate]
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I prefer using the dateutil library for timezone handling and generally solid date parsing. If you were to get an ISO 8601 string like: 2010-05-08T23:41:54.000Z you'd have a fun time parsing that with strptime, especially if you didn't know up front whether or not the timezone was included. ...
How to find where a method is defined at runtime?
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This is really late, but here's how you can find where a method is defined:
http://gist.github.com/76951
# How to find out where a method comes from.
# Learned this from Dave Thomas while teaching Advanced Ruby Studio
# Makes the cas...
Preferred way to create a Scala list
...do so with a tail-recursive function, foldLeft, or something else is not really relevant.
If you get the elements in the same order you use them, then a ListBuffer is most likely a preferable choice, if performance is critical.
But, if you are not on a critical path and the input is low enough, yo...
Error handling in Bash
...kens code's predictability and portability).
You can either let the trap call error for you (in which case it uses the default exit code of 1 and no message) or call it yourself and provide explicit values; for instance:
error ${LINENO} "the foobar failed" 2
will exit with status 2, and give an ...
How to Batch Rename Files in a macOS Terminal?
...g).
If you find yourself batch-renaming files frequently, consider installing a specialized tool such as the Perl-based rename utility.
On macOS you can install it using popular package manager Homebrew as follows:
brew install rename
Here's the equivalent of the command at the top using rena...
How do I get the opposite (negation) of a Boolean in Python?
...ful if you want to use a function that requires a predicate-function or a callback.
For example map or filter:
>>> lst = [True, False, True, False]
>>> list(map(operator.not_, lst))
[False, True, False, True]
>>> lst = [True, False, True, False]
>>> list(filter...
What is the most efficient string concatenation method in python?
... 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. That can tell you which is fastest, instead of r...
Is there any Rails function to check if a partial exists?
..., I'm using the following in my Rails 3/3.1 projects:
lookup_context.find_all('posts/_form').any?
The advantage over other solutions I've seen is that this will look in all view paths instead of just your rails root. This is important to me as I have a lot of rails engines.
This also works in R...
Best way to check if a URL is valid
...mal text. The function or solution, that I'm looking for, should recognize all links formats including the ones with GET parameters.
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