YouTipPython Func Repr
# Python repr() Function
The `repr()` function is a built-in Python function used to obtain a string representation of an object. This representation is typically designed to be unambiguous and, when possible, should match the valid Python code required to recreate the object.
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## Description
The `repr()` function converts an object into a string format suitable for the Python interpreter to read. It is primarily used for debugging and development, as it provides a precise, detailed representation of an object's state.
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## Syntax
The syntax for the `repr()` method is as follows:
```python
repr(object)
```
### Parameters
* **`object`**: The object whose string representation you want to retrieve (e.g., strings, dictionaries, custom class instances, etc.).
### Return Value
Returns a string containing a printable representation of the object.
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## Basic Examples
Here is how `repr()` behaves with built-in Python data types:
```python
>>> s = 'RUNOOB'
>>> repr(s)
"'RUNOOB'"
>>> my_dict = {'runoob': 'runoob.com', 'google': 'google.com'}
>>> repr(my_dict)
"{'runoob': 'runoob.com', 'google': 'google.com'}"
```
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## Advanced Usage: `repr()` vs `str()`
In Python, both `repr()` and `str()` convert objects to strings, but they serve different purposes:
* **`str(object)`**: Designed to return a user-friendly, readable string representation of the object. It is meant for end-users.
* **`repr(object)`**: Designed to return an unambiguous representation of the object, mainly for developers and debugging. For many types, `eval(repr(obj)) == obj` is true.
### Code Comparison
```python
import datetime
today = datetime.datetime.now()
# str() shows a readable format for end-users
print(str(today))
# Output: 2023-10-27 14:30:00.123456
# repr() shows the exact constructor representation for developers
print(repr(today))
# Output: datetime.datetime(2023, 10, 27, 14, 30, 0, 123456)
```
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## Implementing `__repr__()` in Custom Classes
You can control what `repr()` returns for your custom classes by overriding the special `__repr__()` method.
### Example
```python
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
# Define the developer-friendly string representation
def __repr__(self):
return f"Person(name={self.name!r}, age={self.age})"
# Create an instance
p = Person("Alice", 30)
# Call repr() on the instance
print(repr(p))
# Output: Person(name='Alice', age=30)
```
*Note: In the f-string above, `{self.name!r}` automatically calls `repr()` on the `self.name` string, ensuring it is wrapped in quotes inside the output.*