Python, Add + between every third letter

Question

I want be able to add a plus sign (+) for every third letter. For instance,

sequence = ABCDEF

ABC + DEF

I've tried Str.join and it works sorta, but I want it to add a plus sign every third letter.

This is what I have so far.

s = sequence
a = (' + '.join(s))

Answer 1

You could try something like this:

'+'.join(sequence[i:i+3] for i in range(0,len(sequence),3))

Basically what this does is, first, get a sequence of numbers at indices at multiples of 3 using range: range(0,len(sequence),3)

Next, find substrings of length 3 starting from every index: [sequence[i, i+3] for i in range...]

Finally, join these substrings with a '+': '+'.join(...)

Hope this helps.

Answer 2

''.join([your_string[n] if n%3 != 2 else your_string[n]+' + ' for n in range(len(your_string))])

比上一个答案稍微复杂一点，但基本上它创建了一个字符串，其中每个字符都与原始字符串相同，除了每三个字符，它被添加' + ' 。