Type Conversion (Casting & type())0%
Checking Data Types (isinstance)

Type Conversion (Casting & type())

Beginner8 min read•Updated: 2026-09-03
Study Materials

Type Conversion (Casting & type())

Type conversion transforms data from one data type into another.

Key Concepts & Detailed Explanation

Common conversions:

  • int(x): Converts x to integer (truncates floats towards zero).
  • float(x): Converts x to floating point.
  • str(x): Converts any object into its string representation.
  • bool(x): Evaluates truthiness. 0, empty strings, empty lists, and None evaluate to False (falsy); all others are True (truthy).

Code Examples & Output

Python
# Explicit type casting
raw_input = "250"
total = int(raw_input) + 50
print("Total:", total)
 
pi_float = 3.99
print("Truncated:", int(pi_float)) # 3
 
# Truthy and Falsy tests
print("bool(0):", bool(0)) # False
print("bool('hello'):", bool("hello")) # True
print("bool([]):", bool([])) # False

Expected Output:

Output
Total: 300
Truncated: 3
bool(0): False
bool('hello'): True
bool([]): False

Best Practices & Common Pitfalls

Be careful when casting user input with int(). If the string contains non-digits, it raises ValueError.

Practice Quiz

1. What does int('45.5') return?

  • A) 45
  • B) 45.5
  • C) ValueError
  • D) 46
Answer: C Explanation: int() cannot directly parse float strings. Use int(float('45.5')).

2. Which value is considered truthy in Python?

  • A) 0
  • B) []
  • C) "False"
  • D) None
Answer: C Explanation: A non-empty string like 'False' is truthy.

Practice Challenge

Write a program that takes two numerical strings, casts them to floats, and prints their product.

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