Number¶
You can define numeric validations with max and min values for int and float CLI parameters:
import typer
from typing_extensions import Annotated
def main(
id: Annotated[int, typer.Argument(min=0, max=1000)],
age: Annotated[int, typer.Option(min=18)] = 20,
score: Annotated[float, typer.Option(max=100)] = 0,
):
print(f"ID is {id}")
print(f"--age is {age}")
print(f"--score is {score}")
if __name__ == "__main__":
typer.run(main)
🤓 Other versions and variants
Tip
Prefer to use the Annotated version if possible.
import typer
def main(
id: int = typer.Argument(..., min=0, max=1000),
age: int = typer.Option(20, min=18),
score: float = typer.Option(0, max=100),
):
print(f"ID is {id}")
print(f"--age is {age}")
print(f"--score is {score}")
if __name__ == "__main__":
typer.run(main)
CLI arguments and CLI options can both use these validations.
You can specify min, max or both.
Check it:
$ python main.py --help
// Notice the extra RANGE in the help text for --age and --score
Usage: main.py [OPTIONS] ID
Arguments:
ID [required]
Options:
--age INTEGER RANGE [default: 20]
--score FLOAT RANGE [default: 0]
--help Show this message and exit.
// Pass all the CLI parameters
$ python main.py 5 --age 20 --score 90
ID is 5
--age is 20
--score is 90.0
// Pass an invalid ID
$ python main.py 1002
Usage: main.py [OPTIONS] ID
Try "main.py --help" for help.
Error: Invalid value for 'ID': 1002 is not in the range 0<=x<=1000.
// Pass an invalid age
$ python main.py 5 --age 15
Usage: main.py [OPTIONS] ID
Try "main.py --help" for help.
Error: Invalid value for '--age': 15 is not in the range x>=18.
// Pass an invalid score
$ python main.py 5 --age 20 --score 100.5
Usage: main.py [OPTIONS] ID
Try "main.py --help" for help.
Error: Invalid value for '--score': 100.5 is not in the range x<=100.
// But as we didn't specify a minimum score, this is accepted
$ python main.py 5 --age 20 --score -5
ID is 5
--age is 20
--score is -5.0
Clamping numbers¶
You might want to, instead of showing an error, use the closest minimum or maximum valid values.
You can do it with the clamp parameter:
import typer
from typing_extensions import Annotated
def main(
id: Annotated[int, typer.Argument(min=0, max=1000)],
rank: Annotated[int, typer.Option(max=10, clamp=True)] = 0,
score: Annotated[float, typer.Option(min=0, max=100, clamp=True)] = 0,
):
print(f"ID is {id}")
print(f"--rank is {rank}")
print(f"--score is {score}")
if __name__ == "__main__":
typer.run(main)
🤓 Other versions and variants
Tip
Prefer to use the Annotated version if possible.
import typer
def main(
id: int = typer.Argument(..., min=0, max=1000),
rank: int = typer.Option(0, max=10, clamp=True),
score: float = typer.Option(0, min=0, max=100, clamp=True),
):
print(f"ID is {id}")
print(f"--rank is {rank}")
print(f"--score is {score}")
if __name__ == "__main__":
typer.run(main)
And then, when you pass data that is out of the valid range, it will be "clamped", the closest valid value will be used:
// ID doesn't have clamp, so it shows an error
$ python main.py 1002
Usage: main.py [OPTIONS] ID
Try "main.py --help" for help.
Error: Invalid value for 'ID': 1002 is not in the range 0<=x<=1000.
// But --rank and --score use clamp
$ python main.py 5 --rank 11 --score -5
ID is 5
--rank is 10
--score is 0
Counter CLI options¶
You can make a CLI option work as a counter with the counter parameter:
import typer
from typing_extensions import Annotated
def main(verbose: Annotated[int, typer.Option("--verbose", "-v", count=True)] = 0):
print(f"Verbose level is {verbose}")
if __name__ == "__main__":
typer.run(main)
🤓 Other versions and variants
Tip
Prefer to use the Annotated version if possible.
import typer
def main(verbose: int = typer.Option(0, "--verbose", "-v", count=True)):
print(f"Verbose level is {verbose}")
if __name__ == "__main__":
typer.run(main)
It means that the CLI option will be like a boolean flag, e.g. --verbose.
And the value you receive in the function will be the amount of times that --verbose was added:
// Check it
$ python main.py
Verbose level is 0
// Now use one --verbose
$ python main.py --verbose
Verbose level is 1
// Now 3 --verbose
$ python main.py --verbose --verbose --verbose
Verbose level is 3
// And with the short name
$ python main.py -v
Verbose level is 1
// And with the short name 3 times
$ python main.py -v -v -v
Verbose level is 3
// As short names can be put together, this also works
$ python main.py -vvv
Verbose level is 3