Python定义动态函数

您想在源文件中静态地分别定义这些吗?那么最好的选择就是编写一个脚本来生成它们。

另一方面,如果在运行时需要这些函数,可以使用高阶函数。例如。

>>> def make_func(value_to_print):
...     def _function():
...         print value_to_print
...     return _function
...
>>> f1 = make_func(1)
>>> f1()
1
>>> f2 = make_func(2)
>>> f2()
2

>>> my_functions = [make_func(i) for i in range(1, 11)]
>>> for each in my_functions:
...     each()
...
1
2
3
...

确切地 Dynamic/runtime method creation 的 accepted answer 在@Goutham现在删除的答案中提到):

FUNC_TEMPLATE = """def activate_field_{0}(): print({0})"""
for x in range(1, 11): exec(FUNC_TEMPLATE.format(x))

>>> activate_field_1()
1
>>> activate_field_7()
7

f-string 文字:

for x in range(1, 11): exec(f"""def activate_field_{x}(): print({x})""")

vars() :

for i in range(1, 11):
    def f(x):
        def g():
            print x
        return g
    vars()['activate_field_%d' % i] = f(i)

>>> activate_field_3()
3

但是这个技巧通常不会被推荐,除非你确定你需要它。

from functools import partial
class FunctionPool:
    def __init__(self,function):
        self.function = function
    def __getitem__(self,item):
        return partial(self.function,item)

>>> @FunctionPool
def func(item,param):
    print "function#{item} called with {param}".format(
        item = item,
        param = param )
>>> f = func[2]
>>> f(3)
function#2 called with 3