Python:从字符串名称[duplicate]调用函数

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Calling a function of a module by using its name (a string) 10 answers
使用模块的名称(字符串)调用模块的函数10个答案

I have a str object for example: menu = 'install'. I want to run install method from this string. For example when I call menu(some, arguments) it will call install(some, arguments). Is there any way to do that ?

我有一个str对象，例如:menu = 'install'。我想从这个字符串运行install方法。例如，当我调用menu(some, arguments)时，它会调用install(some, arguments)。有什么办法吗?

3 个解决方案

#1

If it's in a class, you can use getattr:

如果是在类中，可以使用getattr:

class MyClass(object):
    def install(self):
          print "In install"

method_name = 'install' # set by the command line options
my_cls = MyClass()

method = None
try:
    method = getattr(my_cls, method_name)
except AttributeError:
    raise NotImplementedError("Class `{}` does not implement `{}`".format(my_cls.__class__.__name__, method_name))

method()

or if it's a function:

或者如果它是一个函数:

def install():
       print "In install"

method_name = 'install' # set by the command line options
possibles = globals().copy()
possibles.update(locals())
method = possibles.get(method_name)
if not method:
     raise NotImplementedError("Method %s not implemented" % method_name)
method()

#2

You can use a dictionary too.

你也可以用字典。

def install():
    print "In install"

methods = {'install': install}

method_name = 'install' # set by the command line options
if method_name in methods:
    methods[method_name]() # + argument list of course
else:
    raise Exception("Method %s not implemented" % method_name)

#3

Why cant we just use eval()?

为什么我们不能使用eval()呢?

def install():
    print "In install"

New method

新方法

def installWithOptions(var1, var2):
    print "In install with options " + var1 + " " + var2

And then you call the method as below

然后调用方法如下所示

method_name1 = 'install()'
method_name2 = 'installWithOptions("a","b")'
eval(method_name1)
eval(method_name2)

This gives the output as

输出为

In install
In install with options a b

#1