sidekick.pred

This module contains a collection of predicate functions that implement common tests. Since all functions are fn-enabled, it accepts bitwise logic to compound predicates into more interesting expressions, like in the example bellow.

>>> sk.filter(sk.is_odd & sk.is_positive, range(-5, 10))
sk.iter([1, 3, 5, 7, 9])

Composing predicates

cond	Conditional evaluation.
any_pred(*predicates)	Return a new predicate function that performs a logic OR to all arguments.
all_pred(*predicates)	Return a new predicate that performs an logic AND to all predicate functions.

Testing values

is_a	Check if x is an instance of cls.
is_equal	Check if x == y.
is_identical	Check if x is y.
is_false	Check if argument is Falseby identity.
is_true	Check if argument is Trueby identity.
is_none	Check if argument is Noneby identity.
is_truthy	Check if argument is truthy.
is_falsy	Check if argument is falsy.

Numeric tests

is_even	Check if argument is even.
is_odd	Check if argument is odd.
is_negative	Check if argument is negative.
is_positive	Check if argument is positive.
is_strictly_negative	Check if argument is strictly negative.
is_strictly_positive	Check if argument is strictly positive.
is_zero	Check if argument is zero.
is_nonzero	Check if argument is nonzero.
is_divisible_by	Check if x is divisible by n.

Sequences

is_distinct	Test if all elements in sequence are distinct.
is_iterable	Test if argument is iterable.
is_seq_equal	Return True if the two sequences are equal.

String tests

has_pattern(pattern[, st])

Check if string contains pattern.

API reference

sidekick.pred.cond

Conditional evaluation.

Return a function that tests the argument with the cond function, and then executes either the then or else_ branches.

Examples

>>> collatz = sk.cond(sk.is_even, _ // 2, (3 * _) + 1)
>>> [collatz(1), collatz(2), collatz(3), collatz(4)]
[4, 1, 10, 2]

sidekick.pred.any_pred(*predicates)

Return a new predicate function that performs a logic OR to all arguments.

This behaves in a short-circuit manner and returns the first truthy result, if found, or the last falsy result, otherwise.

sidekick.pred.all_pred(*predicates)

Return a new predicate that performs an logic AND to all predicate functions.

This behaves in a short-circuit manner and returns the first falsy result, if found, or the last truthy result, otherwise.

sidekick.pred.is_a

Check if x is an instance of cls.

Equivalent to isinstance, but auto-curried and with the order or arguments flipped.

Parameters:

• cls – Type or tuple of types to test for.
• x – Instance.

Examples

>>> is_int = sk.is_a(int)
>>> is_int(42), is_int(42.0)
(True, False)

sidekick.pred.is_equal

Check if x == y.

sidekick.pred.is_identical

Check if x is y.

sidekick.pred.is_false

Check if argument is Falseby identity.

Examples

>>> sk.is_false("not_false")
False
>>> sk.is_false(False)
True

sidekick.pred.is_true

Check if argument is Trueby identity.

Examples

>>> sk.is_true("not_true")
False
>>> sk.is_true(True)
True

sidekick.pred.is_none

Check if argument is Noneby identity.

Examples

>>> sk.is_none("not_none")
False
>>> sk.is_none(None)
True

sidekick.pred.is_truthy

Check if argument is truthy.

This is the same as calling bool(x)

sidekick.pred.is_falsy

Check if argument is falsy.

This is the same as calling not bool(x)

sidekick.pred.is_even

Check if argument is even.

Examples

>>> sk.is_even(1)
False
>>> sk.is_even(42)
True

sidekick.pred.is_odd

Check if argument is odd.

Examples

>>> sk.is_odd(42)
False
>>> sk.is_odd(1)
True

sidekick.pred.is_negative

Check if argument is negative.

Examples

>>> sk.is_negative(42)
False
>>> sk.is_negative(-10)
True

sidekick.pred.is_positive

Check if argument is positive.

Examples

>>> sk.is_positive(-10)
False
>>> sk.is_positive(42)
True

sidekick.pred.is_strictly_negative

Check if argument is strictly negative.

Examples

>>> sk.is_strictly_negative(0)
False
>>> sk.is_strictly_negative(-10)
True

sidekick.pred.is_strictly_positive

Check if argument is strictly positive.

Examples

>>> sk.is_strictly_positive(0)
False
>>> sk.is_strictly_positive(42)
True

sidekick.pred.is_zero

Check if argument is zero.

Examples

>>> sk.is_zero(42)
False
>>> sk.is_zero(0)
True

sidekick.pred.is_nonzero

Check if argument is nonzero.

Examples

>>> sk.is_nonzero(0)
False
>>> sk.is_nonzero(42)
True

sidekick.pred.is_divisible_by

Check if x is divisible by n.

Examples

>>> sk.is_divisible_by(2, 42)  # 42 is divisible by 2
True
>>> even = sk.is_divisible_by(2)
>>> even(4), even(3)
(True, False)

sidekick.pred.has_pattern(pattern, st=NOT_GIVEN)

Check if string contains pattern.

This function performs a pattern scan. If you want to match the beginning of the string, make it start with a “^”. Add a “$” if it needs to match the end.

Examples

>>> sk.has_pattern("\d{2}", "year, 1942")
True
>>> sk.has_pattern("^\d{2}$", "year, 1942")
False

This function is also very useful to filter or process string data.

>>> is_date = sk.has_pattern("^\d{4}-\d{2}-\d{2}$")
>>> is_date("1917-03-08")
True
>>> is_date("08/03/1917")
False

sidekick.pred.is_distinct

Test if all elements in sequence are distinct.

sidekick.pred.is_iterable

Test if argument is iterable.

sidekick.pred.is_seq_equal

Return True if the two sequences are equal.