The trailing I after the regex statement (which in this case is simply the phrase walmart) signifies that the statement is not case sensitive.

regex语句(本例中为walmart)后面的i表明该语句不区分大小写。

youdao

And I don't notice anything except things that are slowing me down: prams that are in my way or people like my wife, trailing behind, whimpering, "Why can't we just stroll?

而且，除非什么东西使我慢下来，我心无旁骛——路上的手推车或者我妻子总会在我的身后表示不满： “为什么我们不能慢慢走？”

youdao

I caught up with a nitrate train, chugging along, its open wagons trailing a gauze of white mist.

有一列拉硝酸钠矿石的火车隆隆前行，敞开的车厢上吹起一阵白雾。

youdao

But I was invited to come, and I would say as a trailing spouse to become, to work as a counselor on the campus of Earlham College, which is a small, really wonderful and far reaching, -Wonderful, wonderful college.

而我是应邀前往，或者说,是当了个跟班的，做了顾问,留在了厄勒姆学院，这是一所规模不大，但非常优秀,影响广泛，-很棒，很棒的学校。

普林斯顿公开课 - 人性课程节选

If we talk about support levels real quick, I think with these indicators proving to be less reliable in turbulent markets, I personally have relied heavily on using trailing stop-loss orders, as I mentioned, as well as indicators like volume, price performance, and support levels.

FORBES: 10 Small Caps Flashing Buy Signs

The two ropes I was trailing added even more weight to every move.

WSJ: Training for the Big Wall | By Michael J. Ybarra

It's cheaper than its peers at 8.1 times trailing earnings and 4 times what I think it should earn in 2013.

FORBES: Magazine Article