asdict and astuple
- Python course
- Intermediate
- Lesson 57/116
- 4 min
Learn conversion with dataclasses.asdict and astuple.
asdict and astuple
The asdict and astuple functions in the dataclasses module convert a dataclass instance to a dict and a tuple respectively. This is useful for passing data in another form.
Example: asdict(p) returns {'x': 3, 'y': 4}; astuple(p) returns (3, 4). Both are imported from the dataclasses module. These conversions are common when exporting data to a dict-expecting API or a database.
Which format for what?
asdict fits when you export data to a dict-expecting API; the keys are the field names. astuple fits when you need ordered access or pass data by position to a function.
Example: you can save a Point instance with save_dict(asdict(p)) and unpack it to a distance function with distance(*astuple(p)). Neither conversion changes the original instance; a new object is returned.
Practice Convert Point to dict and tuple
Start with from dataclasses import dataclass, asdict, astuple. Define a Point class with @dataclass; include fields x: int = 0 and y: int = 0. Then create an instance with p = Point(3, 4) and call print(asdict(p)) and print(astuple(p)).
Starter code
# Convert the Point instance with asdict and astupleSample solution
# Convert the Point instance with asdict and astuple
from dataclasses import dataclass, asdict, astuple
@dataclass
class Point:
x: int = 0
y: int = 0
p = Point(3, 4)
print(asdict(p))
print(astuple(p))Expected output
{'x': 3, 'y': 4}
(3, 4)
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What does asdict(p) return?
- A list
- A tuple
- A dict Correct answer
- A set
Explanation: asdict converts the instance to a dict.
2 Complete the import line
from dataclasses import dataclass, ____
@dataclass
class Point:
x: int = 0
y: int = 0from dataclasses import dataclass, asdict, astuple
@dataclass
class Point:
x: int = 0
y: int = 0Explanation: asdict and astuple are imported together.
3 Match the conversion functions
| Term | Meaning |
|---|---|
asdict |
Converts to dict |
astuple |
Converts to tuple |
{'x': 3, 'y': 4} |
Dict result |
(3, 4) |
Tuple result |