python - Display image as grayscale - Stack Overflow
The following code will load an image from a file image.png and will display it as grayscale.. import numpy as np import matplotlib.pyplot as plt from PIL import Image fname = 'image.png' image = Image.open(fname).convert("L") arr = np.asarray(image) plt.imshow(arr, cmap='gray', vmin=0, vmax=255) plt.show()
python - Plot mean and standard deviation - Stack Overflow
2017年5月23日 · I want to plot the mean and std in python, like the answer of this SO question. I know this must be easy using matplotlib, but I have no idea of the function's name that can do that. I know this must be easy using matplotlib, but I …
python - plot a circle with pyplot - Stack Overflow
2012年2月9日 · Similarly to scatter plot you can also use normal plot with circle line style. Using markersize parameter you can adjust radius of a circle: import matplotlib.pyplot as plt plt.plot(200, 2, 'o', markersize=7)
Matplotlib plt.show () isn't showing graph - Stack Overflow
2015年9月7日 · In this case, since you used plot = plt.figure, you can then type plot.plot(xData, yData), because your variable plot now is part of the figure class. You would use ax for example if you had some additional axes, subplots or color bars on …
Save plot to image file instead of displaying it
2023年12月4日 · import datetime import numpy as np from matplotlib.backends.backend_pdf import PdfPages import matplotlib.pyplot as plt # Create the PdfPages object to which we will save the pages: # The with statement makes sure that the PdfPages object is closed properly at # the end of the block, even if an Exception occurs. with PdfPages('multipage_pdf.pdf ...
why is plotting with Matplotlib so slow? - Stack Overflow
2017年2月14日 · import matplotlib matplotlib.use('GTKAgg') Of course, there are various options to use instead of GTKAgg , but according to the cookbook mentioned before, this was the fastest. See the link about backends for more options.
Matplotlib: using a figure object to initialize a plot
2013年8月17日 · To show a plot you'll want to use fig.canvas.draw() where fig is an instance of the Figure class. fig.canvas.draw() is the API version of the interactive shell (read: pylab ) function draw() If you need to get the Axes or Figure from an AxesImage object you can call either im.get_axes() or im.get_figure() , respectively.
When to use cla (), clf () or close () for clearing a plot
2023年10月2日 · Matplotlib offers these functions: cla() # Clear axis clf() # Clear figure close() # Close a figure window When should I use each function and what exactly does it do?
How to plot 1-d data at given y-value with pylab - Stack Overflow
2012年12月10日 · import numpy as np import matplotlib.pyplot as pp val = 0. # this is the value where you want the data to appear on the y-axis. ar = np.arange(10) # just as an example array pp.plot(ar, np.zeros_like(ar) + val, 'x') pp.show()
matplotlib - Plot x-y data if x entry meets condition python - Stack ...
2014年6月18日 · Sure, just use boolean indexing. You can do things like y = y[x > 10].. E.g. import numpy as np import matplotlib.pyplot as plt #-- Generate some data...----- x = np.linspace(-10, 50, 100) y = x**2 + 3*x + 8 # Add a lot of noise to part of the data... y[x < 10] += np.random.random(sum(x < 10)) * 300 # Now let's extract only the part of the data we're …