Python Learning notes (11) Partial function

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functools.partial is to help us create a biased function, without our own definition int2() , you can create a new function directly using the following code int2 :

Import Functools functools.partial (int, base=2)>>> int2 ('1000000')64>>> int2 ('  1010101')85

So, the simple functools.partial Summary of the function is to put some parameters of a function fixed (that is, set the default), return a new function, call this new function is more simple.

Notice that the new function above int2 simply base sets the parameter back to the default value 2 , but can also pass in other values when the function is called:

>>> int2 ('1000000', base=10)1000000

Finally, when you create a partial function, you can actually receive the function object, *args and **kw These 3 parameters, when passed in:

Int2 = functools.partial (int, base=2)

The key parameter of the int () function is actually fixed base , i.e.:

Int2 ('10010')

Equivalent:

' Base ': 2 }int ('10010', **kw)

When incoming:

Max2 = Functools.partial (max, 10)

Will actually 10 *args add the part automatically to the left, namely:

MAX2 (5, 6, 7)

Equivalent:

args = (5, 6, 7) max (*args)

The result is 10 .

Summary

When a function has too many arguments and needs to be simplified, it functools.partial can be used to create a new function that can fix some of the parameters of the original function , making it easier to invoke.

Python Learning notes (11) Partial function