On 2020-09-17 17:47, Ethan Furman wrote:
On 9/17/20 8:24 AM, William Pearson wrote:
I am puzzled by the reason for this difference between lists and tuples.
A list of with multiple strings can be reduced to a list with one string with
the expected results:
for n in ['first']:
print n
['first'] is a list.
for n in ('first'):
print n
('first') is not a tuple. The tuple operator is actually the comma:
>>> not_a_tuple = ('first')
>>> type(not_a_tuple)
<class 'str'>
>>> is_a_tuple = 'first',
>>> type(is_a_tuple)
<class 'tuple'>
I tend to use both as it makes it stand out a bit more:
>>> still_a_tuple = ('first', )
>>> type(still_a_tuple)
<class 'tuple'>
The only time the parentheses are required for tuple building is when
they would otherwise not be interpreted that way:
They're needed for the empty tuple, which doesn't have a comma.
some_func('first', 'second') # some_func called with two str args
some_func(('first', 'second')) # some_func called with one tuple arg
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