Below shows the output from numpy.ix_() function. What is the use of the output? It’s structure is quite unique. Answer According to numpy doc: Construct an open mesh from multiple sequences. This function takes N 1-D sequences and returns N outputs with N dimensions each, such that the shape is 1 in al…
Tag: numpy-ndarray
Python – Convert Array of Float audio data to wav file
I have audio data recorded from microphone like this : (ndarray of float) This is my code: But when I play the audio it become broken, nothing but just noise… how to convert it into .wav audio file? Answer you need to use pack your data first using struct replace your waveFile.writeframeswith this and m…
Manipulating 2D matrix using numpy boolean indexing takes a long time
I’ve generated a huge amount of random data like so: which is a 100,000 by 1000 matrix(!) I’m generating new matrix where for each row, each column is true if the mean of all the columns beforehand (minus the expectancy of bernoulli RV with p=0.25) is greater than equal some epsilon. like so: Afte…
How do I get the sum of values under a diagonal in numpy?
Given a 2D rectangular numpy array: I would like to take the sum of all values under the lower left to upper right diagonal , I.E. 8, 9 and 6. What is the best way to accomplish this? The method should work for large arrays too. Answer You can rotate, sum the upper triangle, and subtract the diagonal.
Concatenating two one-dimensional NumPy arrays
How do I concatenate two one-dimensional arrays in NumPy? I tried numpy.concatenate: But I get an error: TypeError: only length-1 arrays can be converted to Python scalars Answer Use: The arrays you want to concatenate need to be passed in as a sequence, not as separate arguments. From the NumPy documentation…
How do I calculate percentiles with python/numpy?
Is there a convenient way to calculate percentiles for a sequence or single-dimensional numpy array? I am looking for something similar to Excel’s percentile function. I looked in NumPy’s statistics reference, and couldn’t find this. All I could find is the median (50th percentile), but not …
Convert NumPy array to Python list
How do I convert a NumPy array into a Python List? Answer Use tolist(): Note that this converts the values from whatever numpy type they may have (e.g. np.int32 or np.float32) to the “nearest compatible Python type” (in a list). If you want to preserve the numpy data types, you could call list() o…