Type conversion
- Python course
- Beginner
- Lesson 17/116
- 5 min
Learn type conversions with int(), str(), float().
Type conversion
Converting a value to another type is called type conversion. The functions int(), float(), str(), bool() are used:
age_str = "25"
age = int(age_str) # 25 (int)
price = float("19.99") # 19.99 (float)If the conversion fails Python raises ValueError: int("text") errors. So check the data before converting.
Automatic and explicit conversion
Python converts types automatically in some operations: 5 + 2.0 → 7.0. This is implicit conversion.
In explicit conversion you call a function: int("25"). Explicit conversion is safer and clearer about intent.
When comparing mixed types prefer explicit conversion: int(user_input) > 18.
Practice Convert a string to a number
Assign "25" to age_str. Assign int(age_str) to age. Then print print(age).
Starter code
# Convert the string to a numberSample solution
age_str = "25"
age = int(age_str)
print(age)Expected output
25
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Convert a string to int
age = ____("25")age = int("25")Explanation: int("25") converts the string to an integer.
2 What does int("text") do?
- Returns 0
- Returns None
- Raises an error Correct answer
- Returns an empty string
Explanation: int("text") raises ValueError.
3 Match the conversion functions
| Term | Meaning |
|---|---|
int() |
To integer |
float() |
To float |
str() |
To string |
bool() |
To boolean |