I can accept user's input in two formats:

1. 123
2. 123,234,6028

I need to write a function/a few lines of code that check whether the input follows the correct format.

The rules:

1. If a single number input, then it should be just a number between 1 and 5 digits long
2. If more then one number, then it should be comma-separated values, but without spaces and letters and no comma/period/letter allowed after the last number.

The function just checks if formatting correct, else it prints Incorrect formatting, try entering again.

I would assume I would need to use re module.

Thanks in advance

CodePudding user response：

You can use a simple regex:

import re

validate = re.compile('\d (?:\.\d )?(?:,\d )*')

validate.fullmatch('123')

validate.fullmatch('123.45,678,90')

Use in a test:

if validate.fullmatch(your_string):
    # do stuff
else:
    print('Incorrect formatting, try entering again')

To also allow floats after the first comma: '\d (?:\.\d )?(?:,\d (?:\.\d )?)*')

CodePudding user response：

The following code should leave the Boolean variable valid as True if the entered ibnput complies with your rules and False otherwise:

n = input("Your input: ")
valid = True
try:
    if int(n) > 9999: 
        valid = False
except:
    for character in n:
        if not character in "0123456789,":
            valid = False
    if n[-1] == ",":
        valid = False

CodePudding user response：

Another option is:

def validString(string):
    if not all(
        v.isdigit() for v in string.split(",") if 0 < len(v) < 6
    ):
        print("Incorrect formatting, try entering again.")