Parse a tuple from a string?

Question

Say I have a string that's of the same form a tuple should be, for example, "(1,2,3,4,5)". What's the easiest way to convert that into an actual tuple? An example of what I want to do is:

tup_string = "(1,2,3,4,5)" tup = make_tuple(tup_string) 

Just running tuple() on the string make the whole thing one big tuple, whereas what I'd like to do is comprehend the string as a tuple. I know I can use a regex for this, but I was hoping there's a less costly way. Ideas?

Answer 1

It already exists!

>>> from ast import literal_eval as make_tuple >>> make_tuple("(1,2,3,4,5)") (1, 2, 3, 4, 5) 

Be aware of the corner-case, though:

>>> make_tuple("(1)") 1 >>> make_tuple("(1,)") (1,) 

If your input format works different than Python here, you need to handle that case separately or use another method like tuple(int(x) for x in tup_string[1:-1].split(',')).

Answer 2

I would recommend using literal_eval.

If you are not comfortable with literal_eval or want to have more control on what gets converted you can also disassemble the string, convert the values and recreate the tuple.

Sounds more complicated than it is, really, it's a one-liner:

eg = '(102,117,108)' eg_tuple = map(int, eg.replace('(','').replace(')','').split(','))) 

This would throw a ValueError if any element (string) in the tuple is not convertible to int, like, for example the '1.2' in the string: '(1.2, 3, 4)'.

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The same can be achieved with regex:

import re eg = '(102,117,108)' et_tuple = tuple(map(int, re.findall(r'[0-9]+', eg)))