It's useful for operating on the item the user is currently working with.

这对于操作用户当前正在处理的项目是非常有用的。

youdao

Two key functions for operating on lists (and other sequences of values) are first (which returns the first item) and rest (which returns a list of the rest of the items).

对列表（以及其他值序列）进行操作的两个关键函数是 first（返回第一项）和 rest（返回其余项的清单）。

youdao

Fixed being able to drop your hidden held item when operating the Raft.

修正了在操作救生筏时可以放下隐藏的物品。

youdao

Item No. 1 is the operating expense.

WSJ: Calculating the Costs of Investing in ETFs