I have a set of data as such: I need to iterate over each value in the first column, find the corresponding maximum value in the second column and then store in a new array (or delete the other values from this array). For this example the final output would therefore be: I have managed to write a piece of
Tag: numpy
Different output while using fit_transform vs fit and transform from sklearn
The following code snippet illustrates the issue: Can someone explain as to why the first output is not zero and the second output is? Answer Using this works: Apparently svd_solver = ‘random’ (which is what ‘auto’ defaults to) has enough process difference between .fit(X).transform(X) and fit_transform(X) to give different results even with the same seed. Also remember floating point errors
Rearrange elements in numpy array to plot a 3d array in 2d, preserving grouping
Hello I have a 3d numpy array of shape (nc, nx, ny). I would like to plot it (with matpoltlib) using x and y as the axis, but in such a way that all c values are close to each other and arranged in a rectangle around a central value (you can assume nc is a power of 2). Thanks
How to multiply all numerical columns of a dataframe by a one-dimensional array?
I have a dataframe df of shape r x c, with 1 text column (with non-unique values) and the other columns all floats. I then have an array mult of size r. I would like each numerical column of the dataframe to be multiplied by the corresponding item of the array. Ie the desired output is that value_1[0] should become
How to plot a trend line in a scatter plot from multiple dataframe data?
I have 4 data frames, which are df, df1, df2 and df3.I have plotted these data into a scatter plot. To plot trend line, I use the below code found in stackoverflow. However, this only gives the trendline from df1. I would like to plot a trendline which includes the data from df1, df2 and df3. Answer It uses data
Damping harmonic oscillation code with python
I don’t know that how make the code the three graph in damping harmonic oscillation model, [X – t(time)], [V(velocity) – t(time)], [a(acceleration) – t(time)] graph i can make the [X – t(time)] graph but i don`t know how to make another graphs.. Answer Why can’t you just take the derivative of X to get V and A? Gives,
Fastest method of bilinear weighting of a 2D point cloud onto a grid
Given a point (0.8, 0.6) and an intensity (3), one can bi-linearly “reverse interpolate” a single point onto a 2×2 grid with integer indices (0,0) -> (1,1). The points and grid are oriented with the first entry increasing downwards, and the second entry increasing towards the right. On such a grid, the weight of just the coordinate above becomes: and
Adding new points to point cloud in real time – Open3D
I am using Open3D to visualize point clouds in Python. Essentially, what I want to do is add another point to the point cloud programmatically and then render it in real time. This is what I have so far. I could not find any solution to this. In the code below, I show one possible solution, but it is not
Too many indices for array | python
I’m trying to copy arrays to a pandas Dataframe and get the error “too many indices for array”. The error occurs in these lines: pr_daily and rad_daily are numpy arrays of of the same length. Traceback (most recent call last): File “C:Users…Downloadspython_scriptspv.py”, line 277, in finalDataframe[f’pr_{a_id[index]}’] = (pr_daily[:,index]) IndexError: too many indices for array Answer This error is thrown when
“NameError: name ‘numpy’ is not defined” when calling eval()
The line for e2 (but not e1) generates an error: Why? Answer I solved it by replacing: with: