Python中的无意循环

Question

我刚刚编写了下面的代码，我遇到的问题是，它将显示来自userInput的所有print语句两次，然后给出错误AttributeError: 'function' object has no attribute 'input_voltage'。我对Python还比较陌生，所以任何指导都将非常感激！你知道吗

你知道吗用户输入.py地址：

def InputParameters():
 import testSetup
 test_setup = testSetup.TestCombos
 print("Please input test parameters. Separate multiple test parameters with a comma:\n")
 complete_power_cycle = raw_input("Please select:\n  1. Complete power cycle including both test PC and SSD\n  2. Partial power cycle only including SSD\n")
 cycles = raw_input("Number of cycles: ")                                                                   
 rise_time = raw_input("Rise time: ")
 fall_time = raw_input("Fall time: ")
 overshoot_limit = raw_input("Overshoot voltage: ")
 overshoot_time = raw_input("Overshoot time: ")
 input_voltage = raw_input("Input voltage: ")
 ssd_off_Time = raw_input("Off time between SSD power cycles: ")
 pc_off_time = raw_input("Off time between PC power cycles (if partial power cycle selected, enter none): ")
 temperature = raw_input("Temperature: ")
 test_stop = raw_input("Stop test upon failure? Y/N\n")
 test_setup()

你知道吗测试设置.py地址：

def TestCombos():
 import userInput                                                       
 param = userInput.InputParameters
 output = open('testParamFile.txt', 'w')

 #form combinations from test parameters

 for a in param.input_voltage:
    for b in param.overshoot_limit:
        for c in param.overshoot_time:
            for d in param.rise_time:
                for e in param.fall_time:
                    for f in param.temperature:
                        for g in param.ssd_off_time:
                            for h in param.cycles:
                                for i in param.pc_off_time:
                                    if param.complete_power_cycle == '1':
                                        param_list = [a,b,c,d,e,f,g,i,h]
                                        print(param_list)
                                        #output.write(param_list)
                                    elif param.complete_power_cycle == '2':
                                        param_list = [a,b,c,d,e,f,g,h]
                                        print(param_list)
                                        #output.write(param_list)

Answer 1

我认为您可能误解了Python函数的工作方式。这些变量只存在于InputParameters函数中；如果要在函数外部访问它们，可以返回它们并将它们赋给TestCombos中的变量。你知道吗

我建议您仔细阅读Python的作用域，特别是关于functions和namespaces。你知道吗

Answer 2

这里有一些严重的设计问题，但您要做的是简化代码。不要试图一次得到所有参数的组合，你应该一次得到一个完整的集合，并将它们添加到一个列表中，这样你就有了一个参数列表。你知道吗

用户输入.py

import testSetup  # imports go on top of a file


def get_param_set():
    """
    Returns a list of parameters to be used for testing
    """
    input_messages = [
        "Please select:\n  1. Complete power cycle including both test PC and SSD\n  2. Partial power cycle only including SSD\n",
        "Number of cycles: ",
        "Rise time: ",
        "Fall time: ",
        "Overshoot voltage: ",
        "Overshoot time: ",
        "Input voltage: ",
        "Off time between SSD power cycles: ",
        "Off time between PC power cycles (if partial power cycle selected, enter none): ",
        "Temperature: ",
        "Stop test upon failure? Y/N\n"
    ]
    return [raw_input(message) for message in input_messages]

或者，您可以使用字典，这将使跟踪您的参数更加容易：

def get_param_set():
        """
        Returns a list of parameters to be used for testing
        """
        input_messages = {
            'complete_power_cycle': "Please select:\n  1. Complete power cycle including both test PC and SSD\n  2. Partial power cycle only including SSD\n",
            'cycles': "Number of cycles: ",
            'rise_time': "Rise time: ",
            'fall_time': "Fall time: ",
            'overshoot_limit': "Overshoot voltage: ",
            'overshoot_time': "Overshoot time: ",
            'input_voltage': "Input voltage: ",
            'ssd_off_Time': "Off time between SSD power cycles: ",
            'pc_off_time': "Off time between PC power cycles (if partial power cycle selected, enter none): ",
            'temperature': "Temperature: ",
            'test_stop': "Stop test upon failure? Y/N\n"
        }
        return {key: raw_input(value) for key, value in input_messages.items()}  # you may want to use int(raw_input()) since it looks like most of these will be numbers and 4 != '4'

现在，您将拥有一个如下所示的词典：

{'cycles' '4', 'rise_time': '42', ...}

您只需知道参数名即可访问这些值，而不必知道它的索引，因为索引可能会变得混乱：

>>> param_dict = get_param_set()
>>> param_dict.get('cycles', '0')  # this will give you the value at the key 'cycles' if it's in the dictionary or '0' if it's not.
>>> param_dict['cycles']  # this will also give you the value at the key cycles but it will raise an exception if that key hasn't been set.

测试设置.py

import userInput


def test_combos():
    params = userInput.get_params()
    print(params)
    run_your_test_here(*params)

如果要收集多组参数：

def test_combos(num_of_sets):
    param_sets = [userInput.get_params() for _ in range(num_of_sets)]
    print(params)
    for param_set in param_sets:
        run_your_test_here(*param_set)  # the star unpacks the list into positional arguments

列表解包的快速示例：

>>> def foo(a, b, c):
...     print(a)
...     print(b)
...     print(c)
...
>>> lst = [1,2,3]
>>> foo(*lst)
1
2
3

字典解包：

>>> def foo(a, b, c):
...     print(a)
...     print(b)
...     print(c)
...
>>> bar = {'a': 1, 'c': 3, 'b': 2}
>>> foo(**bar)
1
2
3

请注意，字典的顺序并不重要（字典是无序的集合），只要字典映射中的键与参数名匹配，就可以像执行foo(a=1, b=2, c=3)一样使用它

因此，您可以将一个列表传递给具有多个位置参数的函数。只要len(list)等于位置参数的数量，并且它们的顺序相同，所有的事情都会像你一个接一个地传递它们一样工作。Read more here。你知道吗

在函数内指定的变量在函数作用域外不可用，除非您将其返回并保存到其他变量中。它们可以作为类属性来使用。创建一个新类来运行测试无疑是实现目标的另一种方法。你知道吗

class TestCombo(object):
    def __init__(self):
        # there are better ways to do this but this is simplest to read
        self.complete_power_cycle = raw_input("...")
        self.cycles = raw_input("Number of cycles: ")                                                                   
        self.rise_time = raw_input("Rise time: ")
        self.fall_time = raw_input("Fall time: ")
        self.overshoot_limit = raw_input("Overshoot voltage: ")
        self.overshoot_time = raw_input("Overshoot time: ")
        self.input_voltage = raw_input("Input voltage: ")
        self.ssd_off_Time = raw_input("... ")
        self.pc_off_time = raw_input("...")
        self.temperature = raw_input("Temperature: ")
        self.test_stop = raw_input("...")

    def run_test_combo(self):
        # access class attributes like so
        foo = bar(self.cycles, self.rise_time, ...)
        print(self.test_stop)

要使用类：

>>> test_obj = TestCombo()
# your __init__ method will now run and collect all the inputs
>>> test_obj.test_stop
# will return whatever you set test_stop to be
>>> test_obj.run_test_combo()
# will run whatever code you put inside the method run_test_combo()

因为您似乎正在运行某种测试，所以可以使用内置的^{}模块。你知道吗