functools moduleThe functools module in Python creates higher-order functions that interact with other functions. The higher-order functions either return other functions or operate on them to broaden the scope of the function without modifying or explicitly defining them.
partial methodThe partial() method simplifies the function signature by freezing certain arguments of the passed function. It returns a partial object that behaves like the passed function.
functools.partial(func, /, *args, **keywords)
func: This is the function name.*args: These are positional arguments.**keywords: These are keyword arguments.This method returns a partial object that is callable.
from functools import partialfrom operator import subpartial_sub = partial(sub, 3)diff1 = partial_sub(5)print("partial_sub(5) -", diff1)diff2 = partial_sub(1)print("partial_sub(1) -", diff2)
The sub method from the operator module takes two arguments (x, y) and returns the difference, x - y.
partial method from the functools module and import the sub method from the operator module.sub function by freezing the first argument, x, to always have the value of 3. The partial function is named, partial_sub. Therefore, when we use partial_sub and pass an argument to it, the argument is considered the second argument, y, for the sub function.partial_sub with 5 as the argument. This is equivalent to sub(x=3,y=5). Hence, the value returned is -2. This means 3-5.partial_sub with 1 as the argument. This is equivalent to sub(x=3,y=1). Therefore, the value returned is 2. This means 3-1.partial() on a user-defined functionLet's view another code example of the partial()method:
from functools import partialfrom sre_parse import fix_flagsdef myFunc(arg1, arg2):print("arg1 = %s, arg2 = %s " % (arg1, arg2))fixed_arg1 = "hi"partial_myFunc = partial(myFunc, fixed_arg1)arg2 = "educative"partial_myFunc(arg2)arg2 = "edpresso"partial_myFunc(arg2)
In the code above, we define a user-defined function called myFunc that takes two arguments, arg1 and arg2. We fix/freeze the first argument, arg1, to be hi using the partial function on myFunc. We use the partial object, partial_myFunc, to pass different values for arg1 and arg2.