Add Quotes to Every List Element

I'm very new to python. I need a simple and clear script to add quotes to every list elements. Let me explain more. Here is the my code.

parameters = ['a', 'b', 'c']
query = "SELECT * FROM foo WHERE bar IN (%s)" % (', '.join(parameters))

I want to use this to query. But result is invalid query. Here is the result.

SELECT * FROM foo WHERE bar IN (a, b, c, d)

I want to like this:

SELECT * FROM foo WHERE bar IN ('a', 'b', 'c', 'd')

How to add quotes while joining elements.

3

4 Answers

A naive solution would be to iterate over your parameters list and append quotes to the beginning and end of each element:

(', '.join('"' + item + '"' for item in parameters))

Note: this is vulnerable to SQL injection (whether coincidental or deliberate). A better solution is to let the database quote and insert these values:

query = "SELECT * FROM foo WHERE bar IN (%s)" % ','.join('?' * len(params))
cursor.execute(query, params)

It's easier to read and handles quoting properly.

9

For simple parameters, the following should work:

query = "SELECT * FROM foo WHERE bar IN %s" % repr(tuple(map(str,parameters)))

This may break down when the parameter names themselves include quotes, as the escaping rules are different.

5

As you asked it, use this:

parameters = ['a', 'b', 'c']
', '.join(map(lambda x: "'" + x + "'", parameters))

Since you're creating an SQL query, please use your database library's features regarding input sanitation (example for mysqldb). You don't want to end up with an issue like Bobby Tables.

5

In general (ignoring SQL)

In [3]: print(' '.join('"%s"' % x for x in ['a', 'b']))                                                                                                                                              
"a" "b"

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Elena Rostova

Elena Rostova

Lead Health, Wellness & Medical Journalist

Elena Rostova holds a Master's degree in Public Health Journalism. She covers groundbreaking medical research, holistic wellness trends, mental health awareness, and nutritional science.

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