Convert a list within a list to a string-CodePudding

Let's assume I have the following list: my_lst = [['a', ['b']], ['a1', ['b1']]]. I want to convert it to "a b, a1 b1".

my_lst = [['a', ['b']], ['a1', ['b1']]]
for i in my_lst:
    first_idx = i[0]
    second_idx = i[1][0]
    print(f"{first_idx} {second_idx}", end=",")

My code gives a b,a1 b1,. I don't understand how to remove the comma from the end.

CodePudding user response：

Given

my_lst = [['a', ['b']], ['a1', ['b1', 'b2', 'b3']]]

This

[ [h, *t] for h, t in my_lst ]

gives you

[['a', 'b'], ['a1', 'b1', 'b2', 'b3']]

this

[ ' '.join([h, *t]) for h, t in my_lst ]

returns

['a b', 'a1 b1 b2 b3']

and finally this

', '.join( ' '.join([h, *t]) for h, t in my_lst )

returns

'a b, a1 b1 b2 b3'

which appears to be what you're looking for

CodePudding user response：

Don't print each string in the loop, use join() to combine them with comma separators.

result = ','.join(f"{i[0]} {' '.join(i[1])}" for i in my_lst)
print(result)