# Python In Depth Notes

# My Python Notes
Just bolting down the things I would like to remember.

# General
## F-string

```
x = 1.2000005
f'{x!r}'
f'{x!s}'
f'{x:>+20.6f}'
f'{x:>+20.6e}'
``` 
__format__ delegates to __str__ which in turn delegates to __repr__, so if you don't provide __format__ implementation it will use __str__ if __str__ is not provided either __repr__will be used.
### Example using class

```
``` 



# Class in Python
# String Representation of Objects
# \__repr\__ Function
 \__repr\__ (called as dunder repr) basically stands for representation in Python, used to represent(display) code as string. 

```
class Position:

    def __init__(self, latitude, longitude):
        if not (-90 <= latitude <= +90):
            raise ValueError(f'latitude {latitude} is out of range')
        if not (-180<= longitude <= +180):
            raise ValueError(f'{self.__class__.__name__} longitude {longitude} is out of range')

        self.alatitude = latitude
        self.alongitude = longitude

    def __repr__(self):
        return f'{self.__class__.__name__}(Latitude={self.alatitude}, Longitude={self.alongitude})'

India = Position(60, 90)
print(India)
```
**EXPLANATION OF ABOVE EXAMPLE:**<br/>
i) As in above example a class named 'Position' is created. <br/>
ii) A constructor(\__init\__) is created.<br/>
iii) Criteria of input is defined.<br/>
iv)\__repr\__ function is created which diaplays the string in proper format.<br/>
**OUTPUT:**
```
C:\Users\ashmi\PycharmProjects\Asmi1\venv\Scripts\python.exe C:/Users/ashmi/PycharmProjects/asmi.py/position.py
Position(Latitude=60, Longitude=90)

Process finished with exit code 0
```
**CONVENTIONS FOR GOOD \__repr\__ RESULTS**<br/>
i) **Include appropriate Objects's State** - For smaller objects, it's easy to include all necessary object's state in order to run the function properly. Like in above example, we mentioned class, position and latitude and longitude. <br/> But in case of complex objects, you need to have knowledge to mention only the appropriate objects <br/>
ii) **Format as Constructor**- Your need to format the object so it looks like a constructor call which wouldproduce an object of the same value.