KeepIf 指令

本页为官方文件，一般使用者无法修改，若有任何误谬，请与官方联络。如欲编辑，请至本页的开放版。

KeepIf[ <Condition>, <List> ]

目前本页中文说明尚未翻译完成，请先连至英文说明。如果您有权限，请帮忙翻译本页的官方手册。

KeepIf[Condition, List]

Creates a new list that only contains those elements of the initial list that fulfil the condition.

范例： KeepIf[x<3, {1, 2, 3, 4, 1, 5, 6}] returns the new list {1, 2, 1}.

备注： For list of numbers arbitrary condition may be used. For list of other objects one can use only conditions of the form x==constant or x!=constant.