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A simple collection of validation functions that work on strings, suitable for use in other applications.
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A collection of string-based validation functions, suitable for use in other Python 2 and 3 applications.

Pass a string to these validation functions, which raise ValidationException if validation fails. Otherwise they return a platonic value of the validated string (i.e. the validateInt('42') returns the int 42).


pip install pysimplevalidate


PySimpleValidate provides several functions to perform common input validation. The validate* functions in this module accept a value argument and raise a ValidationException if it doesn't pass validation.

If value was valid, the function returns. The return value is the form of the value that the validation function has accepted as value. This could include any transformations such as stripping whitespace from the ends.

The following (hopefully self-descriptive) validation functions are implemented in this module:

  • validateNum()
  • validateInt()
  • validateFloat()
  • validateChoice()
  • validateDate()
  • validateTime()
  • validateDatetime()
  • validateRegex()
  • validateRegexStr()
  • validateEmail()
  • validateURL()
  • validateYesNo()
  • validateState()
  • validateMonth()
  • validateDayOfWeek()
  • validateDayOfMonth()

These validation functions have the following common parameters:

  • value: (str) The value being validated.
  • blank: (bool) If False, a blank string is considered valid. Defaults to False.
  • strip: (bool, str, None) If omitted or None, whitespace is stripped from value. If a string, the string's characters are stripped from value. If False, nothing is stripped.
  • allowlistRegexes: (Sequence, None) A sequence of regex str that will explicitly pass validation, even if they aren't numbers. Defaults to None.
  • blocklistRegexes: (Sequence, None) A sequence of regex str or (regex_str, response_str) tuples that, if matched, will explicitly fail validation. Defaults to None.

Further, the text-based validators have the following common parameters:

  • caseSensitive (bool): If True, value must match the exact casing of an acceptable response. If False, any casing can be used. Defaults to False.


PySimpleValidate's validation functions will raise ValidationException if the value passed to them fails validation. Otherwise, a cleaned up version of the value is returned.

It's recommended to import PySimpleValidation with the shorter name pysv.

>>> import pysimplevalidate as pysv
>>> pysv.validateStr('I have a cat', allowlistRegexes=['caterpillar', 'cat(.*?)dog'], blocklistRegexes=['cat', 'm(o){2:}se'])
Traceback (most recent call last):
pysimplevalidate.ValidationException: This response is invalid.
>>> pysv.validateStr('I have a caterpillar', allowlistRegexes=['caterpillar', 'cat(.*?)dog'], blocklistRegexes=['cat', 'm(o){2:}se'])
'I have a caterpillar'
>>> pysv.validateStr('I have a cat and a dog', allowlistRegexes=['caterpillar', 'cat(.*?)dog'], blocklistRegexes=['cat', 'm(o){2:}se'])
'I have a cat and a dog'
>>> pysv.validateStr('I have a mooooose', allowlistRegexes=['caterpillar', 'cat(.*?)dog'], blocklistRegexes=['cat', 'm(o){2:}se'])
'I have a mooooose'
>>> pysv.validateNum('42')
>>> pysv.validateNum('twelve')
Traceback (most recent call last):
pysimplevalidate.ValidationException: 'twelve' is not a number.
>>> pysv.validateNum('5', lessThan=10)
>>> pysv.validateFloat('4')
>>> pysv.validateFloat('4.12')
>>> pysv.validateInt('4.12')
Traceback (most recent call last):
pysimplevalidate.ValidationException: '4.12' is not an integer.
>>> pysv.validateChoice('cat', ['dog', 'cat', 'moose'])
>>> pysv.validateChoice('CAT', ['dog', 'cat', 'moose'])
>>> pysv.validateTime('12:00:01')
datetime.time(12, 0, 1)
>>> pysv.validateTime('hour 12 minute 00', formats=['hour %H minute %M'])
datetime.time(12, 0)
>>> pysv.validateEmail('')
>>> pysv.validateURL('')
>>> pysv.validateYesNo('y')
>>> pysv.validateYesNo('NO')
>>> pysv.validateState('California')
>>> pysv.validateState('TEXAS')
>>> pysv.validateState('NY')
>>> pysv.validateDayOfWeek('mon')
>>> pysv.validateDayOfWeek('FRIday')
>>> pysv.validateDayOfMonth(29, 2004, 2)
>>> pysv.validateDayOfMonth(31, 2019, 10)
>>> pysv.validateDayOfMonth(31, 2019, 9)
Traceback (most recent call last):
pysimplevalidate.ValidationException: '31' is not a day in the month of September 2019
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