Printing tuple with string formatting in Python

Question

So, i have this problem. I got tuple (1,2,3) which i should print with string formatting. eg.

tup = (1,2,3)
print \"this is a tuple %something\" % (tup)


        

Answer 1

Please note a trailing comma will be added if the tuple only has one item. e.g:

t = (1,)
print 'this is a tuple {}'.format(t)

and you'll get:

'this is a tuple (1,)'

in some cases e.g. you want to get a quoted list to be used in mysql query string like

SELECT name FROM students WHERE name IN ('Tom', 'Jerry');

you need to consider to remove the tailing comma use replace(',)', ')') after formatting because it's possible that the tuple has only 1 item like ('Tom',), so the tailing comma needs to be removed:

query_string = 'SELECT name FROM students WHERE name IN {}'.format(t).replace(',)', ')')

Please suggest if you have decent way of removing this comma in the output.

Answer 2

Try this to get an answer:

>>>d = ('1', '2') 
>>> print("Value: %s" %(d))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: not all arguments converted during string formatting

If we put only-one tuple inside (), it makes a tuple itself:

>>> (d)
('1', '2')

This means the above print statement will look like: print("Value: %s" %('1', '2')) which is an error!

Hence:

>>> (d,)
(('1', '2'),)
>>> 

Above will be fed correctly to the print's arguments.