[R] Passing formula as parameter to `lm` within `sapply` causes error [BUG?]

[David Winsemius]

Try using do.call

— 
David

Sent from my iPhone

> On Apr 30, 2019, at 9:24 AM, Jens Heumann <jens.heumann using students.unibe.ch> wrote:
> 
> Hi,
> 
> `lm` won't take formula as a parameter when it is within a `sapply`; see example below. Please, could anyone either point me to a syntax error or confirm that this might be a bug?
> 
> Best,
> Jens
> 
> [Disclaimer: This is my first post here, following advice of how to proceed with possible bugs from here: https://www.r-project.org/bugs.html]
> 
> 
> SUMMARY
> 
> While `lm` alone accepts formula parameter `FO` well, the same within a `sapply` causes an error. When putting everything as parameter but formula `FO`, it's still working, though. All parameters work fine within a similar `for` loop.
> 
> 
> MCVE (see data / R-version at bottom)
> 
> > summary(lm(y ~ x, df1, df1[["z"]] == 1, df1[["w"]]))$coef[1, ]
>  Estimate Std. Error    t value   Pr(>|t|)
> 1.6269038  0.9042738  1.7991275  0.3229600
> > summary(lm(FO, data, data[[st]] == st1, data[[ws]]))$coef[1, ]
>  Estimate Std. Error    t value   Pr(>|t|)
> 1.6269038  0.9042738  1.7991275  0.3229600
> > sapply(unique(df1$z), function(s)
> +   summary(lm(y ~ x, df1, df1[["z"]] == s, df1[[ws]]))$coef[1, ])
>                [,1]       [,2]         [,3]
> Estimate   1.6269038 -0.1404174 -0.010338774
> Std. Error 0.9042738  0.4577001  1.858138516
> t value    1.7991275 -0.3067890 -0.005564049
> Pr(>|t|)   0.3229600  0.8104951  0.996457853
> > sapply(unique(data[[st]]), function(s)
> +   summary(lm(FO, data, data[[st]] == s, data[[ws]]))$coef[1, ])  # !!!
> Error in eval(substitute(subset), data, env) : object 's' not found
> > sapply(unique(data[[st]]), function(s)
> +   summary(lm(y ~ x, data, data[[st]] == s, data[[ws]]))$coef[1, ])
>                [,1]       [,2]         [,3]
> Estimate   1.6269038 -0.1404174 -0.010338774
> Std. Error 0.9042738  0.4577001  1.858138516
> t value    1.7991275 -0.3067890 -0.005564049
> Pr(>|t|)   0.3229600  0.8104951  0.996457853
> > m <- matrix(NA, 4, length(unique(data[[st]])))
> > for (s in unique(data[[st]])) {
> +   m[, s] <- summary(lm(FO, data, data[[st]] == s, data[[ws]]))$coef[1, ]
> + }
> > m
>          [,1]       [,2]         [,3]
> [1,] 1.6269038 -0.1404174 -0.010338774
> [2,] 0.9042738  0.4577001  1.858138516
> [3,] 1.7991275 -0.3067890 -0.005564049
> [4,] 0.3229600  0.8104951  0.996457853
> 
> # DATA #################################################################
> 
> df1 <- structure(list(x = c(1.37095844714667, -0.564698171396089, 0.363128411337339,
> 0.63286260496104, 0.404268323140999, -0.106124516091484, 1.51152199743894,
> -0.0946590384130976, 2.01842371387704), y = c(1.30824434809425,
> 0.740171482827397, 2.64977380403845, -0.755998096151299, 0.125479556323628,
> -0.239445852485142, 2.14747239550901, -0.37891195982917, -0.638031707027734
> ), z = c(1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L), w = c(0.7, 0.8,
> 1.2, 0.9, 1.3, 1.2, 0.8, 1, 1)), class = "data.frame", row.names = c(NA,
> -9L))
> 
> FO <- y ~ x; data <- df1; st <- "z"; ws <- "w"; st1 <- 1
> 
> ########################################################################
> 
> > R.version
>               _
> platform       x86_64-w64-mingw32
> arch           x86_64
> os             mingw32
> system         x86_64, mingw32
> status
> major          3
> minor          6.0
> year           2019
> month          04
> day            26
> svn rev        76424
> language       R
> version.string R version 3.6.0 (2019-04-26)
> nickname       Planting of a Tree
> 
> #########################################################################
> 
> NOTE: Question on SO two days ago (https://stackoverflow.com/questions/55893189/passing-formula-as-parameter-to-lm-within-sapply-causes-error-bug-confirmation) brought many views but neither answer nor bug confirmation.
> 
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