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How can I count the occurrences of a list item?
...oop requires a separate pass over the list for every count call, which can be catastrophic for performance. If you want to count all items, or even just multiple items, use Counter, as explained in the other answers.
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Items in JSON object are out of order using “json.dumps”?
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Both Python dict (before Python 3.7) and JSON object are unordered collections. You could pass sort_keys parameter, to sort the keys:
>>> import json
>>> json.dumps({'a': 1, 'b': 2})
'{"b": 2, "a": 1}'
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Defining a variable with or without export
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export makes the variable available to sub-processes.
That is,
export name=value
means that the variable name is available to any process you run from that shell process. If you want a process to make use of this variable, use export, and run ...
Python multiprocessing pool.map for multiple arguments
In the Python multiprocessing library, is there a variant of pool.map which supports multiple arguments?
19 Answers
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R - Concatenate two dataframes?
Given two dataframes a and b :
5 Answers
5
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Test whether a Ruby class is a subclass of another class
I would like to test whether a class inherits from another class, but there doesn't seem to exist a method for that.
2 Answ...
List all base classes in a hierarchy of given class?
... (whether it is a new-style class or not), how do you generate all the base classes - anywhere in the inheritance hierarchy - it issubclass of?
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how to compare two elements in jquery [duplicate]
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You could compare DOM elements. Remember that jQuery selectors return arrays which will never be equal in the sense of reference equality.
Assuming:
<div id="a" class="a"></div>
this:
$('div.a')[0] == $('div#a')[0]
returns true.
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How do I convert a pandas Series or index to a Numpy array? [duplicate]
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To get a NumPy array, you should use the values attribute:
In [1]: df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]}, index=['a', 'b', 'c']); df
A B
a 1 4
b 2 5
c 3 6
In [2]: df.index.values
Out[2]: array(['a', 'b', 'c'], dtype=object)
This accesses how the data ...
How to find common elements from multiple vectors?
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There might be a cleverer way to go about this, but
intersect(intersect(a,b),c)
will do the job.
EDIT: More cleverly, and more conveniently if you have a lot of arguments:
Reduce(intersect, list(a,b,c))
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