Python Coding Day 3 | Data Types: Strings, Integers, and Floats

💻 Data Types: Strings, Integers, and Floats

Watch the lesson tutorial  🔻

In programming, a data type is a classification that tells the compiler or interpreter how the programmer intends to use the data. It essentially defines the type of value a variable can hold and the operations that can be performed on it.

1. String (str) 📝

A string is a sequence of characters. It is used to store text. In most languages, strings are enclosed in either single quotes (') or double quotes (").

• What it stores: Text, words, sentences, symbols, and even numbers (when treated as text).

• Key Feature: Strings are typically immutable, meaning once they are created, they cannot be changed—any operation that appears to "change" a string actually creates a new string.

Practical Example (Python Syntax)

Python

# Storing a name
blog_title = "The University Coder's Guide"

# Storing a complete sentence
post_content = 'Today, we dive into data types.'

# Example of string operations (concatenation and length)
author = "Gemini"
full_line = blog_title + " by " + author
print(full_line)  # Output: The University Coder's Guide by Gemini

# Finding the length of a string
print(len(full_line)) # Output: 40 (counts all characters, including spaces)

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2. Integer (int) 🔢

An integer is a whole number (positive, negative, or zero) without any fractional or decimal part.

• What it stores: Counts, quantities, indices, and any value that must be an exact whole number.

• Key Feature: Modern programming languages often use arbitrary-precision integers, meaning the size of the number is limited only by the computer's memory.

Practical Example (Python Syntax)

Python

# Storing a student's ID number or a course code
student_id = 100345678

# Storing the number of articles published
published_articles = 15

# Example of integer operations (arithmetic)
days_in_week = 7
total_weeks = 4
total_days = days_in_week * total_weeks
print(total_days) # Output: 28

# Checking if a number is an integer
print(isinstance(published_articles, int)) # Output: True

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3. Floating-Point Number (float) 🔬

A floating-point number (or float) is a number that has a decimal point and is used to represent real numbers. The term "floating-point" refers to the way the decimal point "floats" to accommodate a wide range of values.

• What it stores: Measurements, calculations involving division, currency (though often a special Decimal type is preferred), and any value requiring a fractional part.

• Key Consideration: Due to how computers store floats in binary, they can sometimes lead to minor precision errors (e.g., $0.1 + 0.2$ might not exactly equal $0.3$).

Practical Example (Python Syntax)

Python

# Storing a student's GPA
gpa = 3.85

# Storing a measured temperature
temperature = 98.6

# Example of float operations (division and subtraction)
price_of_laptop = 1299.99
sale_discount = 150.50
final_price = price_of_laptop - sale_discount
print(final_price) # Output: 1149.49

# Showing the precision issue (common in all languages)
test_math = 0.1 + 0.2
print(test_math) # Output: 0.30000000000000004 (not exactly 0.3!)

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💡 Quick Comparison Table

Data Type	Represents	Example Value	Enclosure	Usage
string	Textual data	"Hello World"	Quotes (", ')	Names, messages, blog content
int	Whole numbers	42	None	Counts, ages, loop counters
float	Numbers with decimals	3.14159	None	Measurements, financial calculations

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- by Chirana Nimnaka