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How to sum all the values in a dictionary?
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Well,Python 2.7.12 also works well with sum(d.values())
– LancelotHolmes
Jan 17 '17 at 1:14
7
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Why use pip over easy_install? [closed]
...u can pip install ., pip install git+https://.
pip comes with the official Python 2.7 and 3.4+ packages from python.org, and a pip bootstrap is included by default if you build from source.
The various incomplete bits of documentation on installing, using, and building packages have been replaced by...
Making a request to a RESTful API using python
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@ParveenShukhala "Requests officially supports Python 2.6–2.7 & 3.3–3.5, and runs great on PyPy." -- pypi.python.org/pypi/requests
– danio
Dec 15 '16 at 9:10
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Counting the number of True Booleans in a Python List
...th the constant True, a simple sum is fine. However, keep in mind that in Python other values evaluate as True as well. A more robust solution would be to use the bool builtin:
>>> l = [1, 2, True, False]
>>> sum(bool(x) for x in l)
3
UPDATE: Here's another similarly robust so...
How do I raise the same Exception with a custom message in Python?
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Update: For Python 3, check Ben's answer
To attach a message to the current exception and re-raise it:
(the outer try/except is just to show the effect)
For python 2.x where x>=6:
try:
try:
raise ValueError # something...
C++11 std::threads vs posix threads
... almost everywhere and are quite mature. On the other hand if you only use Linux/gcc std::thread is perfectly fine - it has a higher abstraction level, a really good interface and plays nicely with other C++11 classes.
The C++11 std::thread class unfortunately doesn't work reliably (yet) on every p...
pydot and graphviz error: Couldn't import dot_parser, loading of dot files will not be possible
... sudo pip uninstall does not work if you have installed your package using python setup.py install in that case, follow this solution. This was at least the case on my Mountain Lion OSX Mac
– qtips
Aug 6 '13 at 0:43
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Storing Python dictionaries
I'm used to bringing data in and out of Python using CSV files, but there are obvious challenges to this. Are there simple ways to store a dictionary (or sets of dictionaries) in a JSON or pickle file?
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How to use timeit module
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If you want to use timeit in an interactive Python session, there are two convenient options:
Use the IPython shell. It features the convenient %timeit special function:
In [1]: def f(x):
...: return x*x
...:
In [2]: %timeit for x in range(100): f(x)
10...
How do I read image data from a URL in Python?
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In Python3 the StringIO and cStringIO modules are gone.
In Python3 you should use:
from PIL import Image
import requests
from io import BytesIO
response = requests.get(url)
img = Image.open(BytesIO(response.content))
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