I suspect it's an attempt to micro-optimise. join could in theory calculate the target string length before doing any concatenation. I don't know if it does or doesn't. If it does, that means it won't have to expand the string buffer size as it append its arguments.

In reply to Re: Is there a reason to use "join" instead of just using the period? by ikegami
in thread Is there a reason to use "join" instead of just using the period? by qazwart

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