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To plot a transparent histogram with non-transparent edge, we can take the following steps−Create a set of random data points (y).Initialize the number of bins to be drawn.To plot the histogram, we can use hist() method with edge color and facecolor tuplesTo display the figure, use show() method.Exampleimport numpy as np from matplotlib import pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True y = np.random.rand(100) nbins = 5 plt.hist(y, bins=nbins, edgecolor=(1, 0, 0, 1), lw=5, facecolor=(.09, .12, .65, .87), rwidth=0.8) plt.show()Output
To extract csv file for specific columns to list in Python, we can use Pandas read_csv() method.StepsMake a list of columns that have to be extracted.Use read_csv() method to extract the csv file into data frame.Print the exracted data.Plot the data frame using plot() method.To display the figure, use show() method.Exampleimport pandas as pd from matplotlib import pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True columns = ["Name", "Marks"] df = pd.read_csv("input.csv", usecols=columns) print("Contents in csv file:", df) plt.plot(df.Name, df.Marks) plt.show()The csv file contains the following data −NameMarksArun98Shyam75Govind54Javed92Raju87OutputWhen we execute the code, it will extract the data from the csv file ... Read More
To make a log histogram, we can use log=True in the argument of the hist() method.StepsMake a list of numbers.Plot a histogram with density=True.To display the figure, use show() method.Exampleimport numpy as np import matplotlib.pyplot as plt plt.rcParams["figure.figsize"] = [7.50, 3.50] plt.rcParams["figure.autolayout"] = True k = np.array([5, 5, 5, 5]) x, bins, p = plt.hist(np.log(k), density=True, log=True) plt.show()Output
To shade the regions between curves, we can use the fill_between() method.StepsInitialize the variable n. Initiliize x and y data points using numpy.Create a figure and a set of subplots, fig and ax.Plot the curve using plot method.Use fill_between() method, fill the area between the two curves.To display the figure, use show() method.Exampleimport numpy as np import matplotlib.pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True n = 256 X = np.linspace(-np.pi, np.pi, n, endpoint=True) Y = np.sin(2 * X) fig, ax = plt.subplots() ax.plot(X, Y, color='blue', alpha=1.0) ax.fill_between(X, 0, Y, color='blue', alpha=.2) plt.show()OutputRead More
To plot with arrows in matplotlib, we can use arrow() method.StepsCreate x and y data points using numpy.Plot x and y with color=red and linewidth = 1.Use arrow method to add an arrow to the axes. The first two values in the arguments are the coordinates of the arrow base and the next two values are for the length of the arrow along X and Y direction.To display the figure, use show() method.Examplefrom matplotlib import pyplot as plt import numpy as np plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True x = np.linspace(-2, 2, 100) y = np.sin(x) plt.plot(x, y, c='b', ... Read More
To center an annotation horizontally over a point, we can take the following steps−Create points for x and y using numpy.Create labels using xpoints.Use scatter() method to scatter the points.Iterate labels, xpoints and ypoints and annotate the plot with label, x and y with different properties, make horizontal alignment ha=center.To display the figure, use show() method.Exampleimport numpy as np from matplotlib import pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True xpoints = np.linspace(1, 10, 10) ypoints = np.random.rand(10) labels = ["%.2f" % i for i in xpoints] plt.scatter(xpoints, ypoints, c=xpoints) for label, x, y in zip(labels, xpoints, ypoints): ... Read More
To share secondary Y-axis between subplots in matplotlib, we can take the following steps −Create x for data points.Add a subplot to the current figure, with nrows=2, ncols=1, at index=1 (ax0)Using twinx() method, create a twin of axes with a shared X-axis but independent Y-axis (ax1).Add a subplot to the current figure, with nrows=2, ncols=1 at index=2 (ax2)Using twinx() method, create a twin of axes with a shared X-axis but independent Y-axis (ax3).Using get_shared_y_axes() method, return a reference to the shared axes Grouper object for Yaxis.Create curves c1, c2, c3 and c4 with different colors, x and y data points.To move the legend box ... Read More
To read an image in Python cv2, we can take the following steps−Load an image from a file.Display the image in the specified window.Wait for a pressed key.Destroy all of the HighGUI windows.Exampleimport cv2 img = cv2.imread("baseball.png", cv2.IMREAD_COLOR) cv2.imshow("baseball", img) cv2.waitKey(0) cv2.destroyAllWindows()Output
To rotate xtick labels in Seaborn boxplot, we can take the following steps −Create data points for xticks.Draw a boxplot using boxplot() method that returns the axis.Now, set the xticks using set_xticks() method, pass xticks.Set xticklabels and pass a list of labels and rotate them by passing rotation=45, using set_xticklabels() method.To display the figure, use show() method.Exampleimport seaborn as sns from matplotlib import pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True xticks = [1, 4, 5, 2, 3] ax = sns.boxplot(xticks) ax.set_xticks(xticks) ax.set_xticklabels(["one", "two", "three", "four", "five"], rotation=45) plt.show()OutputRead More
To extract matplotlib colormap in hex-format, we can take the following steps −Get the rainbow color map.Iterate in the range of rainbow colormap length.Using rgb2hex method, convert rgba tuple to a hexadecimal representation of a color.Examplefrom matplotlib import cm import matplotlib cmap = cm.rainbow for i in range(cmap.N): rgba = cmap(i) print("Hexadecimal representation of rgba:{} is {}".format(rgba, matplotlib.colors.rgb2hex(rgba)))Output............... ........................ .................................... Hexadecimal representation of rgba:(1.0, 0.3954512068705424, 0.2018824091570102, 1.0) is #ff6533 Hexadecimal representation of rgba:(1.0, 0.38410574917192575, 0.1958454670071669, 1.0) is #ff6232 Hexadecimal representation of rgba:(1.0, 0.37270199199091436, 0.18980109344182594, 1.0) is #ff5f30 .........................................................