如何遍历字典并根据键为变量赋值？答案

【问题标题】：How to loop through a dictionary and assign values to a variable based on keys?如何遍历字典并根据键为变量赋值？
【发布时间】：2021-12-20 10:45:29
【问题描述】：

这让我发疯了，我已经搜索了几个小时，但无法确定这个问题的正面或反面。

通常我会在 SQL 中做这样的事情，但它是 python 模型的一部分，我很难理解变量赋值的工作原理。

我有一本字典（使用 Facebook Prophet 的 GitHub 的语法）：

param_grid = {  
                'changepoint_prior_scale': [.01, 0.05],
                'changepoint_range': [0.8, 0.9],
                'monthly_fourier': [5, 10],
                'monthly_prior_scale': [.01, 0.05],
                'daily_fourier': [5, 10],
                'daily_prior_scale': [.01, 0.05],
                'weekly_fourier': [5, 10],
                'weekly_prior_scale': [.01, 0.05],
                'yearly_fourier': [5],
                'yearly_prior_scale': [.01, 0.05]
              }

然后我创建所有参数排列的字典：

# Generate all combinations of parameters
all_params = [dict(zip(param_grid.keys(), v)) for v in itertools.product(*param_grid.values())]
mape = []  # Store the RMSEs for each params here for later

如下图（供参考）：


print(all_params)
[{'changepoint_prior_scale': 0.01, 'changepoint_range': 0.8, 'monthly_fourier': 5,
'monthly_prior_scale': 0.01, 'daily_fourier': 5, 'daily_prior_scale': 0.01, 'weekly_fourier': 5,
'weekly_prior_scale': 0.01, 'yearly_fourier': 5, 'yearly_prior_scale': 0.01},
{'changepoint_prior_scale': 0.01, 'changepoint_range': 0.8, 'monthly_fourier': 5,
'monthly_prior_scale': 0.01, 'daily_fourier': 5, 'daily_prior_scale': 0.01, 'weekly_fourier': 5,
'weekly_prior_scale': 0.01, 'yearly_fourier': 5, 'yearly_prior_scale': 0.05}....... etc.,]

然后，我要做的就是将每个值传递给它对应的模型组件：

for params in all_params:
    m = Prophet(
        changepoint_prior_scale = all_params['changepoint_prior_scale'],
        changepoint_range = all_params['changepoint_range'],
        seasonality_mode = 'multiplicative',
        growth = 'logistic',
        holidays=Holidays,
        ).add_seasonality(
            name='monthly',
            period=30.5,
            fourier_order = all_params['monthly_fourier'],
            prior_scale = all_params['monthly_prior_scale']
        ).add_seasonality(
            name='daily',
            period=1,
            fourier_order = all_params['daily_fourier'],
            prior_scale = all_params['daily_prior_scale']
etc.,

我知道语法一定是大错特错，但我不知道如何将字典的值分配给模型变量。

例如，我希望第一个模型循环运行：

for params in all_params:
    m = Prophet(
        changepoint_prior_scale = 0.01,
        changepoint_range = 0.8,
        seasonality_mode = 'multiplicative',
        growth = 'logistic',
        holidays=Holidays,
        ).add_seasonality(
            name='monthly',
            period=30.5,
            fourier_order = 5,
            prior_scale = .01
        ).add_seasonality(
            name='daily',
            period=1,
            fourier_order = 5,
            prior_scale = .01
etc.,

我确定这是 python 101，希望有人能帮助我指出正确的方向。

【问题讨论】：

标签： python dictionary for-loop variables facebook-prophet

【解决方案1】：

你已经接近了！看这里

for params in all_params:
    m = Prophet(
        changepoint_prior_scale = all_params['changepoint_prior_scale'],
        changepoint_range = all_params['changepoint_range'],
        seasonality_mode = 'multiplicative',...

请注意，您创建了params，但仍在使用all_params 进行访问！改成这样：

for params in all_params:
        m = Prophet(
            changepoint_prior_scale = params['changepoint_prior_scale'],
            changepoint_range = params['changepoint_range'],
            seasonality_mode = 'multiplicative',...

【讨论】：