英文:
Store results of nested for loop as single concatenated string
问题
I'm sorry, but I can't provide code translation without additional context. If you have any specific questions about the code or need help with a particular part of it, please feel free to ask, and I'll do my best to assist you.
英文:
I'm trying to store the values of the function below to a single string that I can input into a query leveraging an F-string. The output looks correct but is really just a few separated print statements.
How can I store the output of the below to a single string?
import pandas as pd
view_dict = [{'id':'168058','viewtime_min':'2023-01-26 21:00:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'},
{'id':'167268','viewtime_min':'2023-01-26 21:59:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'},
{'id':'167268','viewtime_min':'2023-01-26 21:59:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'}]
def get_where_clause(view_dictionary: dict):
where_clause = " "
for index in range(len(view_dictionary)):
if index != max(range(len(view_dictionary))):
print(f'''(b.id = {view_dictionary[index]['id']}
and b.viewed_at between coalesce({view_dictionary[index]['viewtime_min']},published_at) and {view_dictionary[index]['viewtime_max']})
or''')
else:
print(f'''(b.id = {view_dictionary[index]['id']}
and b.viewed_at between coalesce({view_dictionary[index]['viewtime_min']},published_at) and {view_dictionary[index]['viewtime_max']})''')
x = get_where_clause(view_dict)
x
I'm expecting this to store to a value but when accessing the value nothing is stored.
答案1
得分: 2
你没有实际返回或存储任何东西，print 只是将内容写入控制台。理想情况下，你应该将这些内容收集到类似列表的东西中以便返回，然后可以使用 str.join 连接它们：
view_dict = [{'id':'168058','viewtime_min':'2023-01-26 21:00:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'},
{'id':'167268','viewtime_min':'2023-01-26 21:59:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'},
{'id':'167268','viewtime_min':'2023-01-26 21:59:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'}]
def get_where_clause(view_dictionary: dict):
# 我已经将这个更改为列表
where_clause = []
for index in range(len(view_dictionary)):
if index != max(range(len(view_dictionary))):
where_clause.append(f'''(b.id = {view_dictionary[index]['id']}
and b.viewed_at between coalesce({view_dictionary[index]['viewtime_min']},published_at) and {view_dictionary[index]['viewtime_max']})
or''')
else:
where_clause.append(f'''(b.id = {view_dictionary[index]['id']}
and b.viewed_at between coalesce({view_dictionary[index]['viewtime_min']},published_at) and {view_dictionary[index]['viewtime_max']})''')
# 在这里连接在一起
return ' '.join(where_clause)
x = get_where_clause(view_dict)
print(x)
我知道这不是要求的，但是这可以通过一些基本的迭代技巧进一步简化：
def get_where_clause(view_dictionary: list):
# 我已经将这个更改为列表
where_clause = []
# 获取最后一个元素并在切片上迭代，而不是检查索引
last = view_dictionary[-1]
# 直接迭代视图，不使用索引
for item in view_dictionary[:-1]:
where_clause.append(f'''(b.id = {item['id']}
and b.viewed_at between coalesce({item['viewtime_min']},published_at) and {item['viewtime_max']})
or''')
where_clause.append(f'''(b.id = {last['id']}
and b.viewed_at between coalesce({last['viewtime_min']},published_at) and {last['viewtime_max']})''')
# 在这里连接在一起
return ' '.join(where_clause)
为了简化格式，你可以使用括号来缩进单个字符串：
for item in view_dictionary:
where_clause.append(
f"(b.id = {item['id']} "
"and b.viewed_at between "
f"coalesce({item['viewtime_min']},published_at) "
f"and {item['viewtime_max']})"
)
# 而不是检查第一个/最后一个，你可以连接 'or'
return ' or '.join(where_clause)
英文:
You aren't actually returning or storing anything, print simply writes to the console. Ideally, you'd collect these into something like a list to be returned, which you can then use str.join to concatenate:
view_dict = [{'id':'168058','viewtime_min':'2023-01-26 21:00:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'},
{'id':'167268','viewtime_min':'2023-01-26 21:59:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'},
{'id':'167268','viewtime_min':'2023-01-26 21:59:59.435 -0600','viewtime_max':'2023-01-26 21:59:59.435 -0600'}]
def get_where_clause(view_dictionary: dict):
# I've changed this to a list
where_clause = []
for index in range(len(view_dictionary)):
if index != max(range(len(view_dictionary))):
where_clause.append(f'''(b.id = {view_dictionary[index]['id']}
and b.viewed_at between coalesce({view_dictionary[index]['viewtime_min']},published_at) and {view_dictionary[index]['viewtime_max']})
or''')
else:
where_clause.append(f'''(b.id = {view_dictionary[index]['id']}
and b.viewed_at between coalesce({view_dictionary[index]['viewtime_min']},published_at) and {view_dictionary[index]['viewtime_max']})''')
# join together here
return ' '.join(where_clause)
x = get_where_clause(view_dict)
print(x)
I know it isn't asked for, but this could be cleaned up a little more with some basic iteration techniques:
def get_where_clause(view_dictionary: list):
# I've changed this to a list
where_clause = []
# grab the last element and iterate over a slice
# rather than checking an index
last = view_dictionary[-1]
# iterate over the views directly, don't use an index
for item in view_dictionary[:-1]:
where_clause.append(f'''(b.id = {item['id']}
and b.viewed_at between coalesce({item['viewtime_min']},published_at) and {item['viewtime_max']})
or''')
where_clause.append(f'''(b.id = {last['id']}
and b.viewed_at between coalesce({last['viewtime_min']},published_at) and {last['viewtime_max']})''')
# join together here
return ' '.join(where_clause)
And to simplify formatting, you can indent a single string by using parentheses:
for item in view_dictionary:
where_clause.append(
f"(b.id = {item['id']} "
"and b.viewed_at between "
f"coalesce({item['viewtime_min']},published_at) "
f"and {item['viewtime_max']})"
)
# rather than checking for first/last, you can join on
# 'or'
return ' or '.join(where_clause)
</details>
# 答案2
**得分**: 1
以下是代码部分的翻译：
```py
The `print` command just writes the text to your screen, it does not return a value. Your function needs to return a value for it to be "storable" in a variable.
I rewrote, formatted and commented your code, it now returns a string containing the where clause:
view_dict = [
{
"id": "168058",
"viewtime_min": "2023-01-26 21:00:59.435 -0600",
"viewtime_max": "2023-01-26 21:59:59.435 -0600",
},
{
"id": "167268",
"viewtime_min": "2023-01-26 21:59:59.435 -0600",
"viewtime_max": "2023-01-26 21:59:59.435 -0600",
},
{
"id": "167268",
"viewtime_min": "2023-01-26 21:59:59.435 -0600",
"viewtime_max": "2023-01-26 21:59:59.435 -0600",
},
]
def get_where_clause(view_dictionary: list[dict]) -> str:
# 这是所有输出将存储的地方
outputs = []
# 遍历view_dictionary，实际上是一个字典列表
for vd in view_dictionary:
# 为了提高可读性：从每个字典中获取相关部分
bid = vd['id']
tmin = vd['viewtime_min']
tmax = vd['viewtime_max']
# 将所有内容放入f-string中
output = f"(b.id = {bid} and b.viewed_at between coalesce('{tmin}', published_at) and '{tmax}') or"
# 仅供娱乐，您不会使用此输出
print(output)
# 将每个输出放入outputs列表中
outputs.append(output)
# 通过将所有输出连接成一个字符串来创建实际的WHERE子句
# [:-3] 确保最后的 'or' 关键字被移除
where_clause = " ".join(outputs)[:-3]
return where_clause
x = get_where_clause(view_dict)
英文:
The print command just writes the text to your screen, it does not return a value. Your function needs to return a value for it to be "storable" in a variable.
I rewrote, formatted and commented your code, it now returns a string containing the where clause:
view_dict = [
{
"id": "168058",
"viewtime_min": "2023-01-26 21:00:59.435 -0600",
"viewtime_max": "2023-01-26 21:59:59.435 -0600",
},
{
"id": "167268",
"viewtime_min": "2023-01-26 21:59:59.435 -0600",
"viewtime_max": "2023-01-26 21:59:59.435 -0600",
},
{
"id": "167268",
"viewtime_min": "2023-01-26 21:59:59.435 -0600",
"viewtime_max": "2023-01-26 21:59:59.435 -0600",
},
]
def get_where_clause(view_dictionary: list[dict]) -> str:
# This is where all the outputs will be stored
outputs = []
# Loop over the view_dictionary, which is actually a list of dicts
for vd in view_dictionary:
# Just for readability: get the relevant parts out of each dict
bid = vd['id']
tmin = vd['viewtime_min']
tmax = vd['viewtime_max']
# Place everything in an f-string
output = f"(b.id = {bid} and b.viewed_at between coalesce('{tmin}',published_at) and '{tmax}') or"
# Print, just for fun, you won't use this output
print(output)
# Place every output in the outputs list
outputs.append(output)
# Create the actual WHERE clause by concatenating all outputs into a single string
# the [:-3] makes sure the last 'or' keyword is removed
where_clause = " ".join(outputs)[:-3]
return where_clause
x = get_where_clause(view_dict)
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