Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Data Visualization Articles
Page 8 of 68
Matplotlib – Difference between plt.subplots() and plt.figure()
In Matplotlib, plt.figure() and plt.subplots() are two fundamental functions for creating plots, but they serve different purposes and return different objects. Understanding plt.figure() plt.figure() creates a new figure object or activates an existing one. It returns a Figure object but doesn't create any axes by default. import matplotlib.pyplot as plt import numpy as np # Create a figure using plt.figure() fig = plt.figure(figsize=(8, 5)) fig.suptitle("Using plt.figure()") # Add data manually using plt.plot() x = np.linspace(0, 10, 50) y = np.sin(x) plt.plot(x, y, 'b-', label='sin(x)') plt.xlabel('X values') plt.ylabel('Y values') plt.legend() plt.grid(True) plt.show() ...
Read MoreMatplotlib – How to show the coordinates of a point upon mouse click?
In Matplotlib, you can capture mouse click coordinates on a plot by connecting an event handler to the figure's canvas. This is useful for interactive data exploration and annotation. Setting Up Mouse Click Detection The key is to use mpl_connect() to bind a function to the 'button_press_event' ? import numpy as np import matplotlib.pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True def mouse_event(event): if event.xdata is not None and event.ydata is not None: print('x: {:.3f} and y: {:.3f}'.format(event.xdata, event.ydata)) ...
Read MoreHow to read an input image and print it into an array in matplotlib?
To read an input image and print it into an array in matplotlib, we can use plt.imread() to load the image as a NumPy array and plt.imshow() to display it. Steps Import matplotlib.pyplot Read an image from a file using plt.imread() method Print the NumPy array representation of the image Display the image using plt.imshow() Use plt.axis('off') to hide axis labels Show the plot using plt.show() Example with Sample Data ...
Read MoreHow to create minor ticks for a polar plot in matplotlib?
To create minor ticks for a polar plot in matplotlib, you can manually draw tick marks at specified angular positions. This technique is useful when you need more granular control over tick positioning than the default matplotlib settings provide. Basic Approach The process involves creating radial lines at specific angles to simulate minor ticks. Here's how to implement it ? import numpy as np import matplotlib.pyplot as plt # Set the figure size plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True # Create radius and theta data points r = np.arange(0, 5, 0.1) theta = ...
Read MoreHow to plot an animated image matrix in matplotlib?
To plot an animated image matrix in matplotlib, we can use FuncAnimation to repeatedly update a matrix display. This creates smooth animated visualizations of changing data patterns. Steps Set the figure size and adjust the padding between and around the subplots. Create a figure and a set of subplots. Make an animation by repeatedly calling a function update. Inside the update method, create a 6×6 dimension of matrix and display the data as an image, i.e., on a 2D regular raster. Turn off the axes using set_axis_off(). To display the figure, use show() method. Basic ...
Read MoreHow to put xtick labels in a box matplotlib?
To put xtick labels in a box in matplotlib, we use the set_bbox() method on tick label objects. This creates a visible box around each x-axis label with customizable styling. Steps Create a new figure or activate an existing figure Get the current axis of the figure Position the spines and ticks as needed Iterate through the x-tick labels using get_xticklabels() Apply set_bbox() method with desired box properties Display the figure using show() method Basic Example Here's how to add boxes around x-tick labels ? import matplotlib.pyplot as plt import numpy as ...
Read MoreHow to plot a time as an index value in a Pandas dataframe in Matplotlib?
To plot a time as an index value in a Pandas DataFrame using Matplotlib, you need to set the time column as the DataFrame index. This allows the time values to appear on the x−axis automatically when plotting. Steps Create a DataFrame with time and numeric data columns Convert the time column to datetime format if needed Set the time column as the DataFrame index using set_index() Use the DataFrame's plot() method to create the visualization Basic Time Series Plot Here's how to create a simple time series plot with time as the index ...
Read MoreHow to put a title for a curved line in Python Matplotlib?
To add a title to a curved line plot in Python Matplotlib, you use the plt.title() method after creating your plot. This is essential for making your visualizations clear and informative. Steps Set the figure size and adjust the padding between and around the subplots. Create x and y data points such that the line would be a curve. Plot the x and y data points using plt.plot(). Place a title for the curve plot using plt.title() method. Display the figure using ...
Read MoreMatplotlib – How to plot the FFT of signal with correct frequencies on the X-axis?
To plot the FFT (Fast Fourier Transform) of a signal with correct frequencies on the X-axis in matplotlib, we need to properly compute the frequency bins and visualize the power spectrum. Understanding FFT Frequency Calculation The key to plotting FFT with correct frequencies is using np.fft.fftfreq() which returns the discrete Fourier Transform sample frequencies. For real signals, we typically plot only the positive frequencies using np.fft.rfftfreq(). Basic FFT Plot with Normalized Frequencies Here's how to create a basic FFT plot with normalized frequencies ? import numpy as np import matplotlib.pyplot as plt plt.rcParams["figure.figsize"] ...
Read MoreWhen is plt.Show() required to show a plot and when is it not?
When working with Matplotlib plots, understanding when to use plt.show() is crucial. The requirement depends on your environment — whether you're in an interactive Python session, a Jupyter notebook, or running a script. Interactive vs Non-Interactive Environments In interactive environments like Jupyter notebooks or IPython, plots often display automatically without calling plt.show(). In non-interactive environments like regular Python scripts, you must call plt.show() to display the plot. Basic Example Without plt.show() In Jupyter notebooks, this code displays the plot automatically: import matplotlib.pyplot as plt import numpy as np x = np.linspace(-5, 5, 100) ...
Read More