I find this easier to understand with a visualization. Here I’m using purple ovals for calls to node, green rectangles for calls to cons, black ovals for calls to empty and black rectangles for calls to nil:
英國首名嬰兒透過已故捐贈者子宮移植誕生。业内人士推荐新收录的资料作为进阶阅读
。新收录的资料是该领域的重要参考
Tip: Chaining .filter() then .map() is the most common pipeline. If you need to both filter and transform, this reads more clearly than a manual loop.。新收录的资料对此有专业解读
Targets also included the Guard’s Internal Security’s command center and 50 of its ammunition bunkers, a compound belonging to its Ground Forces, and a base of the Guard’s volunteer Basij force, the army said.
2. 创建计数数组count，统计每个值出现次数