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Beyond input(): Modern Python Techniques for Bulletproof User Input Validation

#rich #input

Beyond Input

Still using input() in your python scripts ?, the same old input method without any data validation and writing it all by yourself. No need to do that any more.

After going through this article, you will be able to validate data input like a PRO!. Thats right, in this article we will see how to validate data input, mask user input in stdio screen, accept data from choices and loop until a valid response is received using python library Rich.

normal to rich

Table of Contents

Installation

Rich can be installed using pip from PyPI or your favorite package manager like rye, uv or poetry etc.

pip install rich
pip gif

rye init --virtual
rye add rich
rye gif

uv init
uv add rich
uv gif

For using rich in Jupyter Notebook or Jupyter Lab, install with additional dependencies using rich[jupyter]

pip install rich[jupyter]

rye init --virtual
rye add rich[jupyter]

uv init
uv add rich[jupyter]

Rich has a number of Prompt classes to ask user for input and loop until it is a valid response. It also provides options to specify default value, choose from a options, entering passwords etc.

prompt Response type
Prompt String
IntPrompt Integer
FloatPrompt Float
Confirm Yes / No

Prompt

Prompt.ask() method returns strings, - Set a default value, which will be returned if the user press enter or return key without entering any value. - Supply a list of choices, the prompt will loop until the user enters one of the choices.

string_prompt.py
from rich.prompt import Prompt
from rich import print

name = Prompt.ask("Enter your name")
print(f"{type(name)=}")
print(f"{name=}")

string prompt

Default value

use default argument to return default value on pressing return key without entering any text.

default_string.py
from rich.prompt import Prompt
from rich import print

name = Prompt.ask("Enter your name", default="Aavishkarah")
print(f"{type(name)=}")
print(f"{name=}")

default_string

Password Input

By default password argument is set to False in prompt.ask(), by setting it to True, the entered text can be hidden from the terminal.

password_input.py
from rich.prompt import Prompt
from rich import print

password = Prompt.ask("Enter your password", password=True)
print(f"{password=}")

password input

Choices

By supplying the list of choices, the prompt will loop until the user enters one of the choices.

choice_input.py
from rich.prompt import Prompt
from rich import print

programming_languages = [
    "Python",
    "Rust",
    "C",
    "Cpp",
    "Java",
    "Go",
]

language = Prompt.ask("Enter your programming language", choices=programming_languages)

print(f"{language=}")

choice_input

Case Insensitive Choices

By default case_sensitive is True, by setting it to False choices can be case insensitive.

Prompt.ask("Enter your choice", 
    choices=choices_list,
    case_sensitive=False
)

Hide Choices

By default show_choices is True, by setting it to False you can hide choices list on the std output screen.

Prompt.ask("Enter your choice", 
    choices=choices_list,
    show_choices=False
)

IntPrompt

By default Prompt.ask() return string. IntPrompt.ask() returns integer data and its keeps looping until an integer data is entered. So no need of converting input data in to integer and writing messy try and except blocks.

integer_data.py
from rich.prompt import IntPrompt
from rich import print

number = IntPrompt.ask("Enter  a number")
print(f"{type(number)=}")
print(f"{number=}")

integer data

FloatPrompt

Similar to IntPrompt.ask() returns integer data, FloatPrompt.ask() keeps looping until a float is entered.

float_data.py
from rich.prompt import FloatPrompt
from rich import print

number = FloatPrompt.ask("Enter a float value")
print(f"{type(number)=}")
print(f"{number=}")

float data

Confirm

Confirm.ask() method is used to ask a yes or no question format.

confirm_prompt.py
from rich.prompt import Confirm
from rich import print

answer = Confirm.ask("Choose your option")
print(f"{type(answer)=}")
print(f"{answer=}")

confirm prompt