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What is the most efficient way to create a dictionary of two pandas Dataframe columns?
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I found a faster way to solve the problem, at least on realistically large datasets using:
df.set_index(KEY).to_dict()[VALUE]
Proof on 50,000 rows:
df = pd.DataFrame(np.random.randint(32, 120, 100000).reshape(50000,2),columns=list('AB'))
df['A'] = df['A'].apply(chr)
%timeit dict(zip(df...
How do I iterate over an NSArray?
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The generally-preferred code for 10.5+/iOS.
for (id object in array) {
// do something with object
}
This construct is used to enumerate objects in a collection which conforms to the NSFastEnumeration protocol. This approach ha...
What's the difference between Unicode and UTF-8? [duplicate]
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most editors support save as ‘Unicode’ encoding actually.
This is an unfortunate misnaming perpetrated by Windows.
Because Windows uses UTF-16LE encoding internally as the memory storage format for Unicode strings, it considers this to be the natural encoding of Unicode tex...
std::vector performance regression when enabling C++11
I have found an interesting performance regression in a small C++ snippet, when I enable C++11:
1 Answer
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Python != operation vs “is not”
...right hand side and the left hand side are the very same object. No methodcalls are done, objects can't influence the is operation.
You use is (and is not) for singletons, like None, where you don't care about objects that might want to pretend to be None or where you want to protect against object...
Logical operators for boolean indexing in Pandas
...Error: The truth value of an array is ambiguous. Use a.empty, a.any() or a.all().
when used as a boolean value. That's because its unclear when it should be True or False. Some users might assume they are True if they have non-zero length, like a Python list. Others might desire for it to be True ...
How can I create a copy of an object in Python?
...would like to create a copy of an object. I want the new object to possess all properties of the old object (values of the fields). But I want to have independent objects. So, if I change values of the fields of the new object, the old object should not be affected by that.
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Get program execution time in the shell
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To see all versions of time you have installed on your system, you can use type -a time
– spinup
Apr 2 '18 at 14:36
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How do I use Java to read from a file that is actively being written to?
I have an application that writes information to file. This information is used post-execution to determine pass/failure/correctness of the application. I'd like to be able to read the file as it is being written so that I can do these pass/failure/correctness checks in real time.
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How to calculate time elapsed in bash script?
...on doesn't depend on date +%s (which is a GNU extension), it's portable to all systems supported by Bash.
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