Base validation functions library¶

Several base validation functions are bundled in the package so as to be reused inside any of the validation entry points provided by valid8.

A quick way to get the up-to-date list of validation functions provided in this package is to execute the following help commands from within a terminal

import valid8.validation_lib

# get the list of submodules containing base validation functions
help(valid8.validation_lib)

# get the list of base validation functions for each submodule
help(valid8.validation_lib.numbers)

# help on a specific function
help(valid8.validation_lib.numbers.is_multiple_of)

If you do not find the function you're looking for in this list, don't hesitate to propose new ones ! Submit a pull request or an issue here.

In parallel, if your function is very specific but writes quite well in plain old python syntax, mini_lambda may provide a good alternative.

Types¶

instance_of(ref_type)¶

'instance of' validation function generator. Returns a validation function to check that is_instance(x, ref_type). If ref_type is a set of types, any match with one of the included types will do.

from valid8 import assert_valid
from valid8.validation_lib import instance_of

assert_valid('Foo', 'r', instance_of(str))

Note that this function can also be used directly in inline codes, by using its 2-args version: instance_of(x, str).

subclass_of(ref_type)¶

'subclass of' validation function generator. Returns a validation function to check that is_subclass(x, ref_type).

from valid8 import assert_valid
from valid8.validation_lib import subclass_of

assert_valid('Foo', bool, subclass_of(int))

Note that this function can also be used directly in inline codes, by using its 2-args version: subclass_of(c, int).

Comparables¶

gt(min_value, strict:bool=False)¶

'Greater than' validation function generator. Returns a validation function to check that x >= min_value (strict=False, default) or x > min_value (strict=True).

gts(min_value)¶

Alias for 'greater than' validation function generator in strict mode.

lt(max_value, strict:bool=False)¶

'Lesser than' validation function generator. Returns a validation function to check that x <= max_value (strict=False, default) or x < max_value (strict=True).

lts(max_value)¶

Alias for 'lesser than' validation function generator in strict mode.

between(min_value, max_value, open_left:bool=False, open_right:bool=False)¶

'Is between' validation function generator. Returns a validation function to check that min_val <= x <= max_val (default). open_right and open_left flags allow to transform each side into strict mode. For example setting open_left=True will enforce min_val < x <= max_val.

Numbers¶

is_even¶

Validates that x is even (x % 2 == 0).

is_odd¶

Validates that x is odd (x % 2 != 0).

is_multiple_of(ref)¶

'Is multiple of' validation function generator. Returns a validation function to check that x is a multiple of the reference (x % ref == 0).

Collections¶

empty¶

'empty' validation function. Raises a NotEmpty error in case of failure.

non_empty¶

'non empty' validation function. Raises a Empty error in case of failure.

has_length(ref_length)¶

'length equals' validation function generator. Returns a validation_function to check that len(x) == ref_length

minlen(min_length)¶

'Minimum length' validation function generator. Returns a validation function to check that len(x) >= min_length.

maxlen(max_length)¶

'Maximum length' validation function generator. Returns a validation function to check that len(x) <= max_length.

length_between(min_len, max_len)¶

'Is length between' validation_function generator. Returns a validation_function to check that min_len <= len(x) <= max_len (default).

is_in(allowed_values)¶

'Values in' validation function generator. Returns a validation function to check that x is in the provided set allowed_values.

is_subset(reference_set)¶

'Is subset' validation function generator. Returns a validation function to check that x is a subset of reference_set. That is, len(x - reference_set) == 0.

contains(ref_value)¶

'Contains' validation_function generator. Returns a validation_function to check that ref_value in x

is_superset(reference_set)¶

'Is superset' validation function generator. Returns a validation function to check that x is a superset of reference_set. That is, len(reference_set - x) == 0.

on_all_(*validation functions_for_all_elts)¶

Generates a validation function for collection inputs where each element of the input will be validated against the validation functions provided. For convenience, a list of validation functions can be provided and will be replaced with an and_.

Note that if you want to apply DIFFERENT validation functions for each element in the input collection, you should rather use on_each_.

on_each_(*validation functions_collection)¶

Generates a validation function for collection inputs where each element of the input will be validated against the corresponding validation function(s) in the validation functions_collection. Validators inside the tuple can be provided as a list for convenience, this will be replaced with an and_ operator if the list has more than one element.

Note that if you want to apply the SAME validation functions to all elements in the input, you should rather use on_all_.