赋值运算符的函数形式是什么,[< - ？

Question

是否有赋值运算符的函数形式？我希望能够用lapply调用作业,如果这是一个坏主意,我总是很好奇.

编辑:

这是一个玩具示例,显然有更好的方法可以做到这一点:

假设我有一个data.frames,dat列表,每个都对应一次实验.我希望能够添加一个新列"主题",并给它一个假名.我想的方式是这样的

lapply(1:3, function(x) assign(data.frame = dat[[x]], column="subject", value=x)

输出可以是修改数据帧的列表,或者修改可以纯粹是副作用.

列表起始列表的输入

list(structure(list(V1 = c(-1.16664504687199, -0.429499924318301,  2.15470735901367, -0.287839633854442, -0.850578353982526, 0.211636723222015,  -0.184714165752958, -0.773553182015158, 0.801811848828454, 1.39420292299319 ), V2 = c(-0.00828185523886259, -0.0215669898046275, 0.743065397283645,  -0.0268464140141802, 0.168027242784788, -0.602901928341917, 0.0740511186398372,  0.180307494696194, 0.131160421341309, -0.924995634374182)), .Names = c("V1",  "V2"), row.names = c(NA, -10L), class = "data.frame"), structure(list(     V1 = c(1.81912921386885, 1.17011641727415, 0.692247839769473,      0.0323050362633069, 1.35816977313292, -0.437475434344363,      -0.270255715332778, 0.96140963297774, 0.914691132220417,      -1.8014509598977), V2 = c(1.45082316226241, 2.05135744606495,      -0.787250759618171, 0.288104852581324, -0.376868533959846,      0.531872044490353, -0.750375220117567, -0.459592764008714,      0.991667163481123, 1.31280356980115)), .Names = c("V1", "V2" ), row.names = c(NA, -10L), class = "data.frame"), structure(list(     V1 = c(0.528912899341174, 0.464615157920766, -0.184211714281637,      0.526909095449027, -0.371529800682086, -0.483772861751781,      -2.02134822661341, -1.30841566046747, -0.738493559993166,      -0.221463545903242), V2 = c(-1.44732101816006, -0.161730785376045,      1.06294520132753, 1.22680614207705, -0.721565979363022, -0.438309438404104,      -0.0243401435910825, 0.624227513999603, 0.276605218579759,      -0.965640602482051)), .Names = c("V1", "V2"), row.names = c(NA,  -10L), class = "data.frame"))

Answer 1

也许我没有得到它,但正如"R编程的艺术"中所述:

左侧不仅仅是标识符(表示变量名称)的任何赋值语句都被视为替换函数.

所以事实上你总是可以翻译这个:

names(x) <- c("a","b","ab")

对此:

x <- "names<-"(x,value=c("a","b","ab"))

一般规则就是 "function_name<-"(<object>, value = c(...))

编辑评论:

它也适用于":

> x <- c(1:3)
> x
[1] 1 2 3
> names(x) <- c("a","b","ab")
> x
 a  b ab 
 1  2  3 
> x
 a  b ab 
 1  2  3 
> x <- c(1:3)
> x
[1] 1 2 3
> x <- "names<-"(x,value=c("a","b","ab"))
> x
 a  b ab 
 1  2  3