ATM PIN Code Validation

Published by Matt in
regexvalidation

ATM machines allow 4 or 6 digit PIN codes and PIN codes cannot contain anything but exactly 4 digits or exactly 6 digits. Your task is to create a function that takes a string and returns true if the PIN is valid and false if it's not.

Examples

is_valid_PIN("1234") ➞ true

is_valid_PIN("12345") ➞ false

is_valid_PIN("a234") ➞ false

is_valid_PIN("") ➞ false

Notes

  • Some test cases contain special characters.
  • Empty strings must return false.
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