Advertisements I am trying to show a light-gray image using plt.imshow(), but the image turns out black. I tried: import matplotlib.pyplot as plt import numpy as np test_image = np.zeros((3871, 2484)) test_image.fill(200) plt.imshow(test_image, cmap="gray") plt.show() But ended up getting: Matplotlib version: 3.7.1 Numpy version: 1.24.3 Python version: 3.11.3 >Solution : Solution You have to include… Read More matplotlib – plt.imshow() of a single color image showing as black

Advertisements I am trying to work on some pixel manipulation on a sequence of images. I encountered an issue when plotting same value of pixel having different color when plotted with different range of pixels. For example, I have an image with six different pixel values(0, 2, 3, 4, 5, 6): Code #1 : import… Read More How to get same color when plotting numpy image array for same pixel value multiple times

Advertisements I am trying to plot stacked bar chart using pandas and matplotlib. I want months to be located on x-axis from datetimes. But It always shows "jan", despite the month given. import matplotlib.pyplot as plt import matplotlib.dates as mdates import pandas as pd from datetime import datetime df = pd.DataFrame({‘value1’:[1,2], ‘value2’:[5,4]}, index=[datetime(year=2020, month=3, day=3),… Read More pandas plot displays wrong months from datetime on x-axis

Advertisements I have a function that takes a list of tuples with float values, from the list I make two new separate lists, each containing the vertex coordinates of the triangle. Then I use matplotlib to draw the vertices. def draw_figure(list_of_floats): x_coord, y_coord = zip(*list_of_floats) x_coord = list(x_coord) y_coord = list(y_coord) # print("Coordinates:") # for… Read More Matplotlib does not draw the last line

Advertisements I saved figure as png file: fig, ax = plt.subplots() … fig.savefig("test.png") Now I want to load this png to figure a plot. I have tried with: fig, ax = plt.subplots() plt.imread("test.png") plt.show() And I’m getting empty figure How can I load this png and show it as plot ? >Solution : To load… Read More How to load png file as figure

Advertisements I have a minimum example of my code as follows: import matplotlib.pyplot as plt fig = plt.figure(1, figsize=(16, 9)) ax = fig.add_subplot(projection=’3d’,elev=-150, azim=110) plt.tight_layout() plt.show() If run my .py script i get following plot with a lot of white spaces on the left and right. Is it possible to fit the subplot to the… Read More Fit Matplotlib 3D subplot to figsize

Advertisements I have two data frames with several columns. I plot df#1 as as stacked bar plot and overlay df #2 as a line plot. If a data series in df#1 is present in df#2 I want the color of the bar segment & line to be the same, for ease of comparison. How would… Read More Using the same color for multiple plots if each dataset contains a common column

Advertisements ax.get_xlim doesnt provide the right result. When running the code below, I get xmin as 1970-01-01 instead of 2003-01-01. Does anyone know how to fix it? data = pd.DataFrame({ ‘Date’: pd.date_range(‘1980-01-01’, ‘2023-01-01′, freq=’M’), ‘Value’: np.random.rand(516) }) data=data.set_index(‘Date’) data.index=pd.to_datetime(data.index) data=data.resample(‘M’).last() data=data[‘2003-01-01’:] fig, ax = plt.subplots() xmin, xmax = ax.get_xlim() ax.plot(data) print(pd.Timestamp(xmin)) >Solution : First, you… Read More ax.get_xlim() doesnt work with datetimeindex

Advertisements With matplotlib’s new subfigure – not subplot – but subfigure feature. I would like to draw a line between two subfigures. From my experimentation, I don’t believe connection patch (which works for subplots) works with this. Does anyone know if it possible? >Solution : You can still use ConnectionPatch with subfigures. Here is an… Read More Draw a line to connect points between subfigures

Advertisements I have below data frame, on which am creating a chart, The expectation is to create as below which is in excel, But while defining the axis in matplotlib, am facing an issue, import matplotlib.pyplot as plt import pandas as pd import random def la_bar(): df1 = pd.DataFrame(lst, columns=[‘source’,’type’,’date’,’count’]) #lst is a data set… Read More raise KeyError(key) KeyError: python matplotlib bar chart key error