如何使用字符串按名称动态调用 Python 函数? [英] How to call Python function by name dynamically using a string?

问题描述

我有一个像这样的 Python 函数调用:

I have a Python function call like so:

import torchvision

model = torchvision.models.resnet18(pretrained=configs.use_trained_models)

哪个工作正常.

如果我试图让它变得动态:

If I attempt to make it dynamic:

import torchvision

model_name = 'resnet18'
model = torchvision.models[model_name](pretrained=configs.use_trained_models)

然后它失败了:

TypeError: 'module' object is not subscriptable

这是有道理的，因为 model 是一个导出一堆东西的模块，包括 resnet 函数:

Which makes sense since model is a module which exports a bunch of things, including the resnet functions:

# __init__.py for the "models" module

...
from .resnet import * 
...

如何在不提前知道函数名称的情况下动态调用这个函数(除了我得到一个带有函数名称的字符串)?

How can I call this function dynamically without knowing ahead of time its name (other than that I get a string with the function name)?

推荐答案

您可以使用 getattr 函数:

You can use the getattr function:

import torchvision

model_name = 'resnet18'
model = getattr(torchvision.models, model_name)(pretrained=configs.use_trained_models)

这基本上与点符号相同，只是在函数形式中接受字符串来检索属性/方法.

This essentially is along the lines the same as the dot notation just in function form accepting a string to retrieve the attribute/method.

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