将变量向量传递给lm()公式 [英] Pass a vector of variables into lm() formula

问题描述

我试图使我的代码片段自动化，以使编程变得不再那么乏味.

I was trying to automate a piece of my code so that programming become less tedious.

基本上，我试图使用 rms 包中的fastbw()逐步选择变量.我想将fastbw()选择的变量列表传递为y ~ x1+x2+x3的公式，"x1""x2""x3"是fastbw()

Basically I was trying to do a stepwise selection of variables using fastbw() in the rms package. I would like to pass the list of variables selected by fastbw() into a formula as y ~ x1+x2+x3, "x1" "x2" "x3" being the list of variables selected by fastbw()

这是我尝试但不起作用的代码

Here is the code I tried and did not work

olsOAW0.r060 <- ols(roll_pct~byoy+trans_YoY+change18m, 
                    subset= helper=="POPNOAW0_r060", 
                    na.action = na.exclude, 
                    data = modelready)

OAW0 <- fastbw(olsOAW0.r060, rule="p", type="residual", sls= 0.05)

vec <- as.vector(OAW0$names.kept, mode="any")

b <- paste(vec, sep ="+") ##I even tried b <- paste(OAW0$names.kept, sep="+")

bestp.OAW0.r060 <- lm(roll_pct ~ b , 
                      data = modelready, 
                      subset = helper =="POPNOAW0_r060",    
                      na.action = na.exclude)

我是R的新手，但仍然没有走过陡峭的学习曲线，因此对明显的编程失误表示歉意.

I am new to R and still haven't trailed the steep learning curve, so apologize for obvious programming blunders.

推荐答案

您快到了.您只需要一起paste 整个公式，就像这样:

You're almost there. You just have to paste the entire formula together, something like this:

paste("roll_pct ~ ",b,sep = "")

使用as.formula将其强制为实际公式，然后将 that 传递给lm.从技术上讲，我认为lm可能会强制转换字符串本身，但是通常自己更强制转换为字符串. (某些期望公式的函数不会为您提供强制性，其他函数则可以.)

coerce it to an actual formula using as.formula and then pass that to lm. Technically, I think lm may coerce a character string itself, but coercing it yourself is generally safer. (Some functions that expect formulas won't do the coercion for you, others will.)

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