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python - 如何循环浏览已定义的元素列表

问题描述

我有一个大型列表字典，它是作为更大的 python 程序的一部分动态生成的。这是字典的外观示例

params = {
'output': ['quantity_tot_1m', 'quantity_tot_3m', 'quantity_tot_6m',
'quantity_tot_12m', 'quantity_tot_full', 'cost_tot_1m', 'cost_tot_3m', 'cost_tot_6m', 'cost_tot_12m', 'cost_tot_full', 'selling_tot_1m', 
'selling_tot_3m', 'selling_tot_6m', 'selling_tot_12m', 'selling_tot_full', 'profit_tot_1m', 'profit_tot_3m', 'profit_tot_6m', 'profit_tot_12m', 'profit_tot_full'], 
'agg_types': ['By SKU - 01 Month','By SKU - 03 Months','By SKU - 06 Months','By SKU - 12 Months']
}

我需要帮助才能循环浏览这些列表

我已经尝试过以下

from jinjasql import JinjaSql
j = JinjaSql(param_style='pyformat')

QUERY_TEMPLATE = """
{% set mix_agg = agg_types|replace("[","")|replace("]","") %}
{% set mix_agg2 = cycler(mix_agg) %}
{% for o in output %}
ROUND(CAST(SUM(CASE WHEN agg_type = '{{ mix_agg2.next() | sqlsafe }}' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS {{o | sqlsafe}} {% endfor%}
"""

query, bind_params = j.prepare_query(QUERY_TEMPLATE, params)
print(query)

这不会循环遍历列表，它只是按原样输出列表。当然，我不能将列表显式输入循环器，因为这必须是动态的。

也许 acycler()不是最好的方法，但我需要如下输出：

ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 01 Month' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_1m,

ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 03 Months' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_3m,

ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 06 Months' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_6m,

ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 12 Months' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_12m

不是这样的：

ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 01 Month', 'By SKU - 03 Months', 'By SKU - 06 Months', 'By SKU - 12 Months' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_1m,

ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 01 Month', 'By SKU - 03 Months', 'By SKU - 06 Months', 'By SKU - 12 Months' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_3m,

ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 01 Month', 'By SKU - 03 Months', 'By SKU - 06 Months', 'By SKU - 12 Months' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_6m,
 
ROUND(CAST(SUM(CASE WHEN agg_type = 'By SKU - 01 Month', 'By SKU - 03 Months', 'By SKU - 06 Months', 'By SKU - 12 Months' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS profit_tot_12m

共有20个输出列{{o | sqlsafe}}

标签： pythonjinja2

解决方案

线

{% set mix_agg = agg_types|replace("[","")|replace("]","") %}

将数组类型转换为字符串，这只会使其以后更难使用，并且可能不是您想要的。

线

{% set mix_agg2 = cycler(mix_agg) %}

然后创建一个带有单个刺的循环器以循环通过 - 因此它将重复返回这个单个字符串。

要循环遍历数组，请使用 python*运算符 - 它将数组转换为函数参数：

{% set mix_agg2 = cycler(*agg_types) %}

综上所述，我们有：

QUERY_TEMPLATE = """
{% set mix_agg2 = cycler(*agg_types) %}
{% for o in output %}
ROUND(CAST(SUM(CASE WHEN agg_type = '{{ mix_agg2.next() | sqlsafe }}' THEN profit_tot ELSE 0 END ) AS NUMERIC),2) AS {{o | sqlsafe}}
{% endfor %}
"""

此外：output包括_tot_full. agg_types您可以通过在定义时添加agg_types或删除它来解决此问题output，或者添加 aif以在循环中跳过它。

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