Histogram in Python

In this article Histogram in Python Learn data visualization using Python’s Matplotlib — create Histograms, Pie Charts, and Sine & Cosine curves with code examples.

Data Visualization in Python: Histogram, Pie Chart, and Sine–Cosine Curves

Data visualization helps to understand data trends and relationships by representing them graphically.
In Python, we commonly use the Matplotlib library for 2D plotting.

Install (if not already):

pip install matplotlib numpy

Then import the modules:

import matplotlib.pyplot as plt

import numpy as np

1. Histogram

Definition:

A histogram shows how data is distributed across different intervals (called bins).
It’s useful for visualizing the frequency distribution of numerical data.

Example Code:

import matplotlib.pyplot as plt

import numpy as np

# Generate random data

data = np.random.randn(1000)  # 1000 random values (Normal Distribution)

plt.hist(data, bins=20, color=’skyblue’, edgecolor=’black’)

plt.title(“Histogram of Random Data”)

plt.xlabel(“Data Range”)

plt.ylabel(“Frequency”)

plt.grid(axis=’y’, alpha=0.75)

plt.show()

Output Explanation:

• The X-axis shows data ranges (bins).
• The Y-axis shows how many data points fall in each bin.
• It helps detect patterns, outliers, or spread of data.

2. Pie Chart

Definition:

A Pie Chart displays data as a circular graph divided into slices, each representing a category’s proportion.

Example Code:

import matplotlib.pyplot as plt

# Data for pie chart

labels = [‘Python’, ‘Java’, ‘C++’, ‘JavaScript’]

sizes = [40, 25, 20, 15]

colors = [‘gold’, ‘lightcoral’, ‘lightskyblue’, ‘lightgreen’]

explode = (0.1, 0, 0, 0)  # explode the 1st slice (Python)

plt.pie(sizes, labels=labels, colors=colors, autopct=’%1.1f%%’,

        startangle=90, shadow=True, explode=explode)

plt.title(“Programming Language Popularity”)

plt.show()

Output Explanation:

• Each slice shows the percentage share of each programming language.
• The explode parameter highlights a slice.
• The autopct displays percentages inside the chart.

3. Sine and Cosine Curves

Definition:

The Sine and Cosine curves are basic trigonometric functions used to represent periodic (wave-like) data.
These functions are essential in mathematics, physics, and engineering.

Example Code:

import matplotlib.pyplot as plt

import numpy as np

# Create data points

x = np.linspace(0, 2 * np.pi, 100)  # 0 to 2π

y1 = np.sin(x)

y2 = np.cos(x)

plt.plot(x, y1, label=’Sine Wave’, color=’blue’, linewidth=2)

plt.plot(x, y2, label=’Cosine Wave’, color=’red’, linestyle=’–‘, linewidth=2)

plt.title(“Sine and Cosine Curves”)

plt.xlabel(“Angle (radians)”)

plt.ylabel(“Amplitude”)

plt.legend()

plt.grid(True)

plt.show()

Output Explanation:

• The Sine wave starts at 0.
• The Cosine wave starts at 1.
• Both waves repeat every 2π2\pi2π radians.

Summary Table

Key Points

• Use plt.title(), plt.xlabel(), and plt.ylabel() to make plots readable.
• Always call plt.show() to display the figure.
• Combine multiple plots with plt.subplot() if required.

POP- Introduction to Programming Using ‘C’

DS – Data structure Using C

OOP – Object Oriented Programming 

Java Programming

DBMS – Database Management System

RDBMS – Relational Database Management System

https://defineinfoloop.blogspot.com/?m=1