同学你好，该知识点来自沪江网校《BEC商务英语初、中、高级连读【爆款特惠签约班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好，
by the way 在词典中有如下解释：第一种为： a phrase indicating that the speaker is adding information. 增加信息 Tom: Is this one any good? Clerk: This is the largest and, by the way, the most expensive one we have in stock. 第二种为：a phrase indicating that the speaker is casually opening a new subject.  打断现在目前的话题，随意地开启一个新话题 如：Bill: Oh, by the way, Fred, do you still have that hammer you borrowed from me? Fred: I'll check. I thought I gave it back.
如果同学在这里想要表达顺便的话by the way可能不太合适，因为它更强调顺便（说，提一下），建议你可以用 I can drop by a friend. 我会顺便拜访一个朋友。drop by表示一种非正式的拜访，用在相熟的朋友间是可以的。
希望对你有所帮助，祝学习愉快！