What does the c underscore expression `c_` do exactly?
Use IPython’s ? syntax to get more information:
numpy
Factorial in numpy and scipy
You can import them like this: scipy.math.factorial and numpy.math.factorial seem to simply be aliases/references for/to math.factorial, that is scipy.math.factorial is math.factorial and numpy.math.factorial is math.factorial should both give True.
ImportError: numpy.core.multiarray failed to import
I’m trying to run this program But I’m having a problem with numpy, I’m using pyschopy along with opencv. The problem I keep getting is this error report: RuntimeError: module compiled against API version 7 but this version of numpy is 6 Traceback (most recent call last): File “C:\Users\John\Documents\EyeTracking\Programs\GetImage.py”, line 1, in ImportError: numpy.core.multiarray failed … Read more
What does numpy.random.seed(0) do?
np.random.seed(0) makes the random numbers predictable With the seed reset (every time), the same set of numbers will appear every time. If the random seed is not reset, different numbers appear with every invocation: (pseudo-)random numbers work by starting with a number (the seed), multiplying it by a large number, adding an offset, then taking modulo of that sum. The … Read more
Data type not understood while creating a NumPy array
You are missing brackets around the two lists. The way it was written the dtype argument was receiving the value [79000,3.9,16933.26], which obviously cannot be interpreted as a valid NumPy data type and caused the error.
Should I use np.absolute or np.abs?
It’s likely because there a built-in functions with the same name, abs. The same is true for np.amax, np.amin and np.round_. The aliases for the NumPy functions abs, min, max and round are only defined in the top-level package. So np.abs and np.absolute are completely identical. It doesn’t matter which one you use. There are several advantages to the short names: They are shorter and they are known to Python … Read more
How to normalize a NumPy array to a unit vector?
If you’re using scikit-learn you can use sklearn.preprocessing.normalize:
Plotting a 2D heatmap with Matplotlib
The imshow() function with parameters interpolation=’nearest’ and cmap=’hot’ should do what you want.
How do I read CSV data into a record array in NumPy?
You can use Numpy’s genfromtxt() method to do so, by setting the delimiter kwarg to a comma. More information on the function can be found at its respective documentation.
How do you do natural logs (e.g. “ln()”) with numpy in Python?
np.log is ln, whereas np.log10 is your standard base 10 log. Relevant documentation: http://docs.scipy.org/doc/numpy/reference/generated/numpy.log.html http://docs.scipy.org/doc/numpy/reference/generated/numpy.log10.html