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How to check whether a pandas DataFrame is empty?
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Dave Thomas
1,38922 gold badges1010 silver badges1616 bronze badges
answered Nov 7 '13 at 5:55
aIKidaIKid
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Performance of foreach, array_map with lambda and array_map with static function
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122
FWIW, I just did the benchmark since poster didn't do it. Running on PHP 5.3.10 + XDebug.
UPD...
How to randomly sort (scramble) an array in Ruby?
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293
Built in now:
[1,2,3,4].shuffle => [2, 1, 3, 4]
[1,2,3,4].shuffle => [1, 3, 2, 4]
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How to switch position of two items in a Python list?
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i = ['title', 'email', 'password2', 'password1', 'first_name',
'last_name', 'next', 'newsletter']
a, b = i.index('password2'), i.index('password1')
i[b], i[a] = i[a], i[b]
sh...
What is the difference between an int and a long in C++?
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112
It is implementation dependent.
For example, under Windows they are the same, but for example...
Running a cron job at 2:30 AM everyday
How to configure a cron job to run every night at 2:30? I know how to make it run at 2, but not 2:30.
6 Answers
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Concatenating two one-dimensional NumPy arrays
...separate arguments.
From the NumPy documentation:
numpy.concatenate((a1, a2, ...), axis=0)
Join a sequence of arrays together.
It was trying to interpret your b as the axis parameter, which is why it complained it couldn't convert it into a scalar.
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python numpy ValueError: operands could not be broadcast together with shapes
...iplication, but * does something else.
We have two arrays:
X, shape (97,2)
y, shape (2,1)
With Numpy arrays, the operation
X * y
is done element-wise, but one or both of the values can be expanded in one or more dimensions to make them compatible. This operation are called broadcasting. Dime...
How to update SQLAlchemy row entry?
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answered Mar 12 '12 at 12:49
DenisDenis
5,62966 gold badges3535 silver badges5454 bronze badges
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Booleans, conditional operators and autoboxing
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92
The difference is that the explicit type of the returnsNull() method affects the static typing o...