最Pythonic的方法来进行输入验证 [英] Most Pythonic way to do input validation

问题描述

在Python中进行用户输入验证的最正确"的Pythonic方法是什么?

What is the most "correct", Pythonic way to do user input validation in Python?

我一直在使用以下内容:

I've been using the following:

while True:
    stuff = input("Please enter foo: ")
    try:
        some_test(stuff)
        print("Thanks.")
        break
    except SomeException:
        print("Invalid input.")

我想这很好而且可读性很好，但是我不禁要问是否没有内置函数或应该使用的内置函数.

Which is nice and readable, I suppose, but I can't help wondering if there isn't some built-in function or something I should be using instead.

推荐答案

我喜欢装饰器，以将检查与其余输入处理分开.

I like decorators to separate the checking from the rest of the input handling.

#!/usr/bin/env python

def repeatOnError(*exceptions):
  def checking(function):
    def checked(*args, **kwargs):
      while True:
        try:
          result = function(*args, **kwargs)
        except exceptions as problem:
          print "There was a problem with the input:"
          print problem.__class__.__name__
          print problem
          print "Please repeat!"
        else: 
          return result
    return checked
  return checking

@repeatOnError(ValueError)
def getNumberOfIterations():
  return int(raw_input("Please enter the number of iterations: "))

iterationCounter = getNumberOfIterations()
print "You have chosen", iterationCounter, "iterations."

装饰器或多或少是现有功能(或方法)的包装.它获取现有功能(在其@decorator指令下方表示)，并为其返回替换".在我们的案例中，此替换在循环中调用原始函数，并捕获在此过程中发生的任何异常.如果没有异常发生，则只返回原始函数的结果.

A decorator is more or less a wrapper for an existing function (or method). It takes the existing function (denoted below its @decorator directive) and returns a "replacement" for it. This replacement in our case calls the original function in a loop and catches any exception happening while doing so. If no exception happens, it just returns the result of the original function.

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