如何在 python 字符串格式中仅添加不带括号的列表值

Question

In the code below, how can I remove the brackets in the output?

In [11]: xx = [1,2,3,4]

In [12]: print('%s BLAH' %xx)
[1, 2, 3, 4] BLAH

I would like the output to be:

1, 2, 3, 4 BLAH

I am looking for a general solution, NOT something like below (I want to use %s only once):

print('%s %s %s %s BLAH' %tuple(xx))

Answer 1

You have to join the list to a string:

print('%s BLAH' % ', '.join(xx))

Answer 2

Straightforward way would be to use join()

>>> a
[1, 2, 3, 4]
>>> ', '.join([str(x) for x in a])
'1, 2, 3, 4'
>>> 

If you want to not use join then override the str dunder function of the list class. Please see below:

class FancyList(list):
    def __repr__(self):
        fancy_output = ''
        for item in self:
            fancy_output += f'{item}, '
        return fancy_output.strip().strip(',')

    def __str__(self):
        return self.__repr__()

if __name__ == "__main__":
    a = [1,2,3,4]
    print(a)
    fancy_a = FancyList(a)
    print(fancy_a)
    print('%s BLAH' % fancy_a)
    fancy_a.append(100)
    print(fancy_a)
    print('%s BLAH' % fancy_a)

which gives me output:

[1, 2, 3, 4]
1, 2, 3, 4
1, 2, 3, 4 BLAH
1, 2, 3, 4, 100
1, 2, 3, 4, 100 BLAH

Answer 3

You actually can do it without %s with this code:

print(', '.join(xx) + " BLAH")