Matplotlib.pyplot.hist() in Python

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

matplotlib.pyplot.hist() Function

The hist() function in pyplot module of matplotlib library is used to plot a histogram.

Syntax: matplotlib.pyplot.hist(x, bins=None, range=None, density=False, weights=None, cumulative=False, bottom=None, histtype=’bar’, align=’mid’, orientation=’vertical’, rwidth=None, log=False, color=None, label=None, stacked=False, \*, data=None, \*\*kwargs)

Parameters: This method accept the following parameters that are described below:

• x : This parameter are the sequence of data.
• bins : This parameter is an optional parameter and it contains the integer or sequence or string.
• range : This parameter is an optional parameter and it the lower and upper range of the bins.
• density : This parameter is an optional parameter and it contains the boolean values.
• weights : This parameter is an optional parameter and it is an array of weights, of the same shape as x.
• bottom : This parameter is the location of the bottom baseline of each bin.
• histtype : This parameter is an optional parameter and it is used to draw type of histogram. {‘bar’, ‘barstacked’, ‘step’, ‘stepfilled’}
• align : This parameter is an optional parameter and it controls how the histogram is plotted. {‘left’, ‘mid’, ‘right’}
• rwidth : This parameter is an optional parameter and it is a relative width of the bars as a fraction of the bin width
• log : This parameter is an optional parameter and it is used to set histogram axis to a log scale
• color : This parameter is an optional parameter and it is a color spec or sequence of color specs, one per dataset.
• label : This parameter is an optional parameter and it is a string, or sequence of strings to match multiple datasets.
• normed : This parameter is an optional parameter and it contains the boolean values.It uses the density keyword argument instead.

Returns: This returns the following:

• n :This returns the values of the histogram bins.
• bins :This returns the edges of the bins.
• patches :This returns the list of individual patches used to create the histogram.

Below examples illustrate the matplotlib.pyplot.hist() function in matplotlib.pyplot:

Example #1:

# Implementation of matplotlib function
import matplotlib
import numpy as np
import matplotlib.pyplot as plt

np.random.seed(10**7)
mu = 121
sigma = 21
x = mu + sigma * np.random.randn(1000)

num_bins = 100

n, bins, patches = plt.hist(x, num_bins,
                            density = 1,
                            color ='green',
                            alpha = 0.7)

y = ((1 / (np.sqrt(2 * np.pi) * sigma)) *
     np.exp(-0.5 * (1 / sigma * (bins - mu))**2))

plt.plot(bins, y, '--', color ='black')

plt.xlabel('X-Axis')
plt.ylabel('Y-Axis')

plt.title('matplotlib.pyplot.hist() function Example\n\n',
          fontweight ="bold")

plt.show()

Output:

Example #2:

# Implementation of matplotlib function
import matplotlib
import numpy as np
import matplotlib.pyplot as plt

np.random.seed(10**7)
n_bins = 20
x = np.random.randn(10000, 3)

colors = ['green', 'blue', 'lime']

plt.hist(x, n_bins, density = True,
         histtype ='bar',
         color = colors,
         label = colors)

plt.legend(prop ={'size': 10})

plt.title('matplotlib.pyplot.hist() function Example\n\n',
          fontweight ="bold")

plt.show()

Output: