Matplotlib Articles - Page 68 of 91

To add apha to an existing matplotlib colormap, we can take the following steps −Create data with a 4×4 dimension array using numpy.Get the colormap using plt.cm.RdBU.Create a new colormap using numpy.Set alpha value to the new colormap.Generate a colormap object using the list of colors.Create a new figure or activate an existing figure using figure() method.Add a subplot to the current figure, nrows=1, ncols=2 at index=1.Create a pseudocolor plot with a non-regular rectangular grid using pcolormesh() method.Create a colorbar for scalar mappable instance.Repeat steps 7 to 9, at index 2.Use tight_layout() to adjust the padding between and around the subplots.To ... Read More

To annotate a heatmap with text in matplotlib, we can take the following steps −Create random data with 4×4 dimension array.Create a pseudocolor plot with a non-regular rectangular grid, using pcolor() method.To put text in the pixels, we can use text() method.To display the figure, use show() method.Exampleimport matplotlib.pyplot as plt import numpy as np plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True data = np.random.rand(4, 4) heatmap = plt.pcolor(data, cmap="PuBuGn_r") for y in range(data.shape[0]):    for x in range(data.shape[1]):       plt.text(x + 0.5, y + 0.5, '%.4f' % data[y, x],          horizontalalignment='center',         ... Read More

To make superscript or subscript text in matplotlib, use LaTeX representation.StepsCreate x and y data points using numpy.Plot x and y data point using plot() method.Put the title with LateX representation using title() method.Use xlabel and ylabel methods to set the label of the axes.Exampleimport numpy as np from matplotlib import pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True x = np.linspace(-2, 2, 10) y = 2**x plt.plot(x, y) plt.title('$Y=2^{X}$') plt.xlabel('$X_{data}$') plt.ylabel('$Y_{data}$') plt.show()Output

To change the spacing of dashes in a dashed line in matplotlib, we can take the following steps −Create data points x and y using numpy.Initialize two variables space and dash_len with value 3.Plot x and y using plot() method, with line style '--', dashes tuple stores the property of dashed line.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 x = np.linspace(-1, 1, 100) y = np.sin(x) space = 3 dash_len = 3 plt.plot(x, y, c='red', linestyle='--', dashes=(dash_len, space), lw=5) plt.show()OutputRead More

To set the ticks on a fixed position in matplotlib, we can take the following steps −Create a figure and add a set of subplots.To set the ticks on a fixed position, create two lists with some values.Use set_yticks and set_xticks methods to set the ticks on the axes.To display the figure, use show() method.Exampleimport matplotlib.pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True fig, ax = plt.subplots() xtick_loc = [0.20, 0.75, 0.30] ytick_loc = [0.12, 0.80, 0.76] ax.set_xticks(xtick_loc) ax.set_yticks(ytick_loc) plt.show()Output

To rotate xtick labels through 90 degrees, we can take the following steps −Make a list (x) of numbers.Add a subplot to the current figure.Set ticks on X-axis.Set xtick labels and use rotate=90 as the arguments in the method.To display the figure, use show() method.Exampleimport matplotlib.pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True x = [1, 2, 3, 4] ax1 = plt.subplot() ax1.set_xticks(x) ax1.set_xticklabels(["one", "two", "three", "four"], rotation=90) plt.show()Output

To plot multiple histograms on same plot with Seaborn, we can take the following steps −Create two lists (x and y).Create a figure and add a set of two subplots.Iterate a list consisting of x and y.Plot a histogram with histplot() method using the data in the list (step 3).Limit the X-axis range from 0 to 10.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 x = [1, 5, 1, 4, 2] y = [7, 5, 6, 4, 5] fig, ax = plt.subplots() for a in [x, y]: ... Read More

To annotate time series plot in matplotlib, we can take the following steps −Create lists for time and numbers.Using subplots() method, create a figure and a set of subplots.Using plot_date() method, plot the data that contains dates with linestyle "-.".Annotate a point in the plot using annotate() method.Date ticklabels often overlap, so it is useful to rotate them and right-align them.To display the figure, use show() method.Exampleimport datetime as dt from matplotlib import pyplot as plt, dates as mdates plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True x = [dt.datetime(2021, 1, 1), dt.datetime(2021, 1, 2),    dt.datetime(2021, 1, 3), dt.datetime(2021, 1, 4)] y = ... Read More

To insert statistical annotation, we can take the following steps −Create lists (x and y) of numbers.Using subplots() method, create a figure and a set of subplots.Using plot() method, plot the data that contains dates with linestyle "-.".Annotate a point in the plot using annotate() method, mean of x and y.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 x = np.linspace(-1, 1, 5) y = np.linspace(-2, 2, 5) mean_x = np.mean(x) mean_y = np.mean(y) fig, ax = plt.subplots() ax.plot(x, y, linestyle='-.') ax.annotate('*', (mean_y, mean_y), xytext=(-.50, 1), arrowprops=dict(arrowstyle='-|>')) ... Read More

To annotate data points while plotting from pandas data frame, we can take the following steps −Create df using DataFrame with x, y and index keys.Create a figure and a set of subplots using subplots() method.Plot a series of data frame using plot() method, kind='scatter', ax=ax, c='red' and marker='x'.To annotate the scatter point with the index value, iterate the data frame.To display the figure, use show() method.Exampleimport numpy as np import pandas as pd from matplotlib import pyplot as plt import string plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True df = pd.DataFrame({'x': np.random.rand(10), 'y': np.random.rand(10)}, index=list(string.ascii_lowercase[:10])) fig, ax = plt.subplots() df.plot('x', ... Read More