Enclose each element in a string-tuple with quotes

Question

I need to query to a database and filter on a where link in (....). The issue is the (...) since that "tuple" is dynamic. If I do it like this:

input_links = get_links() # [<link1>,...]
query = f"SELECT * from myTable where link in {tuple(input_links)}

that works fine unless input_links contains one link then the last part becomes (link1,) thus breaking the query.

I've tried using

input_links = get_links() # [<link1>,...]
link_tpl = f'({",".join(input_links)})'
query = f"SELECT * from myTable where link in {link_tpl}

but that encloses the entire argument in the tuple in one quote e.g ('link1,link2,link3') instead of ('link1','link2','link3').

I know I can just do an

if len(input_links)==1:
   query = f"SELECT * from myTable where link={input_links[0]}"
else:
   f"SELECT * from myTable where link in {tuple(input_links)}

but it just bothers me that I cannot have it as one statement.

```f'(",".join(input_links))'``` should be ```(",".join(input_links))'``` — , Aug 12 '21 at 05:43
True, thats a typo in the question (it was formatted correctly in the code) — CutePoison, Aug 12 '21 at 05:47
Any particular reason you're not using a prepared statement for this? In addition to the safety benefits, it seems like it would be easier in this case — Green Cloak Guy, Aug 12 '21 at 05:51

score 3 · Answer 1 · answered Aug 12 '21 at 05:57

3

You can map each item in input_links to a string formatter:

query = f'''SELECT * from myTable where link=({', '.join(map("'{}'".format, input_links))})'''

answered Aug 12 '21 at 05:57

blhsing

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1

Upvote! Excellent use of `map`; learned something new. Thanks! – S3DEV Aug 12 '21 at 07:49

Brian Destura · Accepted Answer · 2021-08-12T06:13:44.833

1

Had this headache a few weeks back. Ended up doing something like this:

'(%s)' % ', '.join(map(repr, input_links))

Output:

   ...: input_links = [link1]
   ...: print('(%s)' % ', '.join(map(repr, input_links)))
   ...:
   ...: input_links = [link1, link2]
   ...: print('(%s)' % ', '.join(map(repr, input_links)))
(link1)
(link1, link2)

Based from this answer.

edited Aug 12 '21 at 06:13

answered Aug 12 '21 at 05:57

Brian Destura

11,487
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34

score 0 · Answer 3 · answered Aug 12 '21 at 05:54

Check this out. Assuming the links as '1','2'...:

l=['1','2']
def check_tup(l):
    k=','.join(f"'{i}'" for i in l)
    return f'({k})'
print(f"SELECT * from myTable where link in {check_tup(l)}")

Outputs:

SELECT * from myTable where link in ('1','2')

If l=['1']:

SELECT * from myTable where link in ('1')

Enclose each element in a string-tuple with quotes

3 Answers3