الدوال الجزئية

ما هي partial؟

from functools import partial
def power(base, exp):
    return base ** exp
square = partial(power, exp=2)
print(square(5))

تثبيت الوسائط الموضعية

from functools import partial
def multiply(a, b):
    return a * b
double = partial(multiply, 2)
print(double(10))
print(double(50))

تثبيت الوسائط المسماة

from functools import partial
def greet(name, greeting='Hello'):
    return greeting + ', ' + name
hola = partial(greet, greeting='Hola')
print(hola('Ada'))
print(hola('Bob', greeting='Hey'))

استخدام partial مع الدوال المضمنة

from functools import partial
binary = partial(int, base=2)
print(binary('1010'))
print(binary('1111'))

دوال رد اتصال أوضح

from functools import partial
def log(level, message):
    return '[' + level + '] ' + message
error = partial(log, 'ERROR')
print(error('disk full'))

استخدام partials مع map

from functools import partial
def add(a, b):
    return a + b
add10 = partial(add, 10)
print(list(map(add10, [1, 2, 3])))

فحص دالة جزئية

from functools import partial
def f(a, b, c):
    return (a, b, c)
p = partial(f, 1, c=3)
print(p.func.__name__)
print(p.args)
print(p.keywords)

تكديس الدوال الجزئية

from functools import partial
def volume(l, w, h):
    return l * w * h
base = partial(volume, 2)
slab = partial(base, 3)
print(slab(4))

partial مقابل lambda

from functools import partial
def power(base, exp):
    return base ** exp
cube_p = partial(power, exp=3)
cube_l = lambda b: power(b, 3)
print(cube_p(2), cube_l(2))

مثال عملي: التقريب

from functools import partial
round2 = partial(round, ndigits=2)
print(round2(3.14159))
print(round2(2.71828))

partialmethod للفئات

from functools import partialmethod
class Light:
    def set(self, state):
        self.state = state
        return state
    on = partialmethod(set, True)
    off = partialmethod(set, False)
l = Light()
print(l.on())
print(l.off())

تحقق سريع

مراجعة: الدوال الجزئية

from functools import partial
add = lambda a, b: a + b
plus1 = partial(add, 1)
print(plus1(41))