# [R] NA command in a 'for' loop

Rui Barradas ru|pb@rr@d@@ @end|ng |rom @@po@pt
Tue Apr 21 20:38:48 CEST 2020

```Hello,

Much better, you have "," at the end of your data elements so nothing is
working.

The following 3 instructions

1. remove those commas,
2. create a logical vector trying to guess which columns are numeric
3. coerce those columns to numeric.

d[] <- lapply(d, function(x){sub(",\$", "", x)})
not_num <- sapply(d, function(x) all(is.na(as.numeric(as.character(x)))))
d[!not_num] <- lapply(d[!not_num], function(x) as.numeric(as.character(x)))

Then, if you want just d\$V13 == 0 to become NA, this will do it.

is.na(d[["V13"]]) <- d[["V13"]] == 0

If you want to do this to all numeric columns, try

d[!not_num] <- lapply(d[!not_num], function(x){
is.na(x) <- x == 0
x
})

Hope this helps,

Às 18:11 de 21/04/20, Helen Sawaya escreveu:
> Thank you for your patience.
>
> This is the output of dput(head(d, 10))
>
> structure(list(V1 = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
> 1L, 1L), .Label = "9.9761E+11,", class = "factor"), V2 = structure(c(1L,
> 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "threat,", class = "factor"),
>      V3 = structure(c(1L, 28L, 37L, 48L, 55L, 63L, 73L, 88L, 2L,
>      20L), .Label = c("1,", "10,", "100,", "101,", "102,", "104,",
>      "107,", "108,", "109,", "110,", "111,", "112,", "113,", "114,",
>      "115,", "116,", "117,", "118,", "119,", "12,", "13,", "14,",
>      "15,", "16,", "17,", "18,", "19,", "2,", "20,", "21,", "22,",
>      "23,", "24,", "27,", "28,", "29,", "3,", "30,", "31,", "32,",
>      "33,", "34,", "35,", "36,", "37,", "38,", "39,", "4,", "42,",
>      "44,", "46,", "47,", "48,", "49,", "5,", "50,", "52,", "53,",
>      "54,", "55,", "57,", "59,", "6,", "60,", "61,", "62,", "63,",
>      "64,", "65,", "66,", "68,", "69,", "7,", "71,", "74,", "75,",
>      "76,", "78,", "81,", "82,", "83,", "84,", "85,", "86,", "87,",
>      "88,", "89,", "9,", "90,", "91,", "92,", "94,", "95,", "96,",
>      "97,", "98,"), class = "factor"), V4 = structure(c(1L, 2L,
>      1L, 2L, 2L, 2L, 2L, 2L, 1L, 1L), .Label = c("1,", "2,"), class = "factor"),
>      V5 = structure(c(2L, 2L, 2L, 1L, 2L, 1L, 1L, 2L, 2L, 2L), .Label = c("1,",
>      "2,"), class = "factor"), V6 = structure(c(2L, 1L, 2L, 2L,
>      1L, 2L, 2L, 1L, 2L, 2L), .Label = c("1,", "2,"), class = "factor"),
>      V7 = structure(c(2L, 1L, 2L, 2L, 2L, 2L, 1L, 2L, 1L, 2L), .Label = c("1,",
>      "2,"), class = "factor"), V8 = structure(c(41L, 92L, 63L,
>      36L, 2L, 81L, 12L, 14L, 23L, 33L), .Label = c("abduction,",
>      "abortion,", "abuse,", "accident,", "addicted,", "agony,",
>      "anger,", "angry,", "anguish,", "assault,", "bankrupt,",
>      "bullet,", "burial,", "cancer,", "cemetery,", "coffin,",
>      "corpse,", "crash,", "crisis,", "cruel,", "death,", "defeated,",
>      "depressed,", "deserted,", "despair,", "destroy,", "disaster,",
>      "disloyal,", "distress,", "dreadful,", "drown,", "dull,",
>      "dump,", "emaciated,", "failure,", "fatigue,", "fault,",
>      "feeble,", "fever,", "filth,", "forlorn,", "germs,", "gloomy,",
>      "hardship,", "hell,", "helpless,", "horror,", "hostage,",
>      "hostile,", "hurt,", "idiot,", "infest,", "injury,", "irritable,",
>      "jail,", "killer,", "lonely,", "malaria,", "messy,", "misery,",
>      "mistake,", "morbid,", "murder,", "mutilate,", "pain,", "panic,",
>      "poison,", "prison,", "pus,", "rape,", "rat,", "rejected,",
>      "sad,", "scum,", "shame,", "sick,", "slap,", "snake,", "spider,",
>      "suicide,", "surgery,", "terrible,", "tormented,", "trash,",
>      "trauma,", "ugly,", "ulcer,", "unease,", "unhappy,", "useless,",
>      "victim,", "wasp,", "weep,", "worm,", "wound,"), class = "factor"),
>      V9 = structure(c(24L, 90L, 73L, 10L, 92L, 33L, 84L, 96L,
>      70L, 57L), .Label = c("alley,", "ankle,", "appliance,", "audience,",
>      "bandage,", "bathroom,", "bookcase,", "border,", "branch,",
>      "cabinet,", "category,", "clean,", "cliff,", "cold,", "consider,",
>      "consoled,", "context,", "country,", "crop,", "dentist,",
>      "detail,", "dinner,", "doctor,", "dynamic,", "easygoing,",
>      "elbow,", "energetic,", "farm,", "faucet,", "flat,", "flowing,",
>      "fork,", "freezer,", "glass,", "grass,", "guess,", "humble,",
>      "icebox,", "industry,", "invisible,", "jug,", "lighting,",
>      "lion,", "listen,", "little,", "machine,", "metal,", "month,",
>      "mushroom,", "napkin,", "news,", "noisy,", "north,", "nudge,",
>      "number,", "numerous,", "obey,", "odd,", "oval,", "plant,",
>      "possible,", "pot,", "public,", "puzzled,", "quarter,", "rational,",
>      "ready,", "reflect,", "reliable,", "repentant,", "sand,",
>      "school,", "secret,", "series,", "shark,", "shoe,", "shop,",
>      "shortened,", "skyline,", "stable,", "storm,", "stove,",
>      "table,", "theory,", "tower,", "truck,", "upgrade,", "upright,",
>      "utensil,", "vest,", "vision,", "volcano,", "walk,", "watchful,",
>      "window,", "winter,"), class = "factor"), V10 = structure(c(1L,
>      1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "NA,", class = "factor"),
>      V11 = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "NA,", class = "factor"),
>      V12 = structure(c(2L, 1L, 2L, 2L, 2L, 2L, 1L, 2L, 1L, 2L), .Label = c("203,",
>      "205,"), class = "factor"), V13 = structure(c(1L, 1L, 1L,
>      1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "1,", class = "factor"),
>      V14 = c(4063L, 4914L, 1508L, 1819L, 1228L, 992L, 1898L, 1174L,
>      1294L, 1417L)), row.names = c(NA, 10L), class = "data.frame”)
>
> When I use the following:
>
> all.files <- list.files(".")
> txt.files <- grep("threat.txt",all.files,value=T)
>
> for(i in txt.files) {
>    d[] <- lapply(d, function(x) {is.na(x) <- x == 0; x})
>    write.table(d,paste0(i, "trial.txt"), quote=FALSE, row.names=FALSE)}
>
> I get this (an example of one of the output files with zeros in V13):
>
> V1 V2 V3 V4 V5 V6 V7 V8 V9 V10 V11 V12 V13 V14
> 3.17903E+11, threat, 1, 1, 2, 2, 1, useless, flowing, NA, NA, 203, 1, 949
> 3.17903E+11, threat, 3, 2, 2, 1, 1, hostage, skyline, NA, NA, 203, 1, 1116
> 3.17903E+11, threat, 4, 1, 1, 1, 2, messy, ready, NA, NA, 205, 1, 1277
> 3.17903E+11, threat, 6, 2, 1, 2, 2, emaciated, shortened, NA, NA, 205, 1, 691
> 3.17903E+11, threat, 7, 1, 1, 1, 1, abuse, plant, NA, NA, 203, 1, 660
> 3.17903E+11, threat, 8, 2, 1, 2, 2, tormented, easygoing, NA, NA, 205, 1, 812
> 3.17903E+11, threat, 9, 1, 2, 2, 2, hurt, sand, NA, NA, 205, 1, 917
> 3.17903E+11, threat, 10, 1, 1, 1, 1, surgery, freezer, NA, NA, 203, 1, 1829
> 3.17903E+11, threat, 12, 2, 2, 1, 2, accident, category, NA, NA, 205, 1, 821
> 3.17903E+11, threat, 13, 2, 1, 2, 2, terrible, energetic, NA, NA, 205, 1, 783
> 3.17903E+11, threat, 14, 1, 2, 2, 1, wound, storm, NA, NA, 203, 1, 813
> 3.17903E+11, threat, 15, 1, 1, 1, 2, victim, utensil, NA, NA, 205, 1, 1132
> 3.17903E+11, threat, 16, 2, 2, 1, 2, bankrupt, lighting, NA, NA, 203, 0, 1510
> 3.17903E+11, threat, 17, 1, 1, 1, 2, anguish, country, NA, NA, 203, 0, 811
> 3.17903E+11, threat, 18, 2, 2, 1, 1, snake, table, NA, NA, 203, 1, 805
> 3.17903E+11, threat, 19, 1, 1, 1, 2, slap, crop, NA, NA, 205, 1, 1180
> 3.17903E+11, threat, 20, 2, 1, 2, 2, scum, shoe, NA, NA, 205, 1, 792
> 3.17903E+11, threat, 21, 1, 2, 2, 1, weep, shop, NA, NA, 203, 1, 870
> 3.17903E+11, threat, 23, 2, 1, 2, 1, spider, border, NA, NA, 203, 1, 871
>
> str(d) gives me the following:
>
> 'data.frame':	96 obs. of  14 variables:
>   \$ V1 : Factor w/ 1 level "9.9761E+11,": 1 1 1 1 1 1 1 1 1 1 ...
>   \$ V2 : Factor w/ 1 level "threat,": 1 1 1 1 1 1 1 1 1 1 ...
>   \$ V3 : Factor w/ 96 levels "1,","10,","100,",..: 1 28 37 48 55 63 73 88 2 20 ...
>   \$ V4 : Factor w/ 2 levels "1,","2,": 1 2 1 2 2 2 2 2 1 1 ...
>   \$ V5 : Factor w/ 2 levels "1,","2,": 2 2 2 1 2 1 1 2 2 2 ...
>   \$ V6 : Factor w/ 2 levels "1,","2,": 2 1 2 2 1 2 2 1 2 2 ...
>   \$ V7 : Factor w/ 2 levels "1,","2,": 2 1 2 2 2 2 1 2 1 2 ...
>   \$ V8 : Factor w/ 95 levels "abduction,","abortion,",..: 41 92 63 36 2 81 12 14 23 33 ...
>   \$ V9 : Factor w/ 96 levels "alley,","ankle,",..: 24 90 73 10 92 33 84 96 70 57 ...
>   \$ V10: Factor w/ 1 level "NA,": 1 1 1 1 1 1 1 1 1 1 ...
>   \$ V11: Factor w/ 1 level "NA,": 1 1 1 1 1 1 1 1 1 1 ...
>   \$ V12: Factor w/ 2 levels "203,","205,": 2 1 2 2 2 2 1 2 1 2 ...
>   \$ V13: Factor w/ 1 level "1,": 1 1 1 1 1 1 1 1 1 1 ...
>   \$ V14: int  4063 4914 1508 1819 1228 992 1898 1174 1294 1417 …
>
> When I use this:
>
> for(i in txt.files) {
>    d2<-d[d\$V13==1,]
>    write.table(d2,sub("[.]",".trial.",i),quote=FALSE,row.names=FALSE)
> }
>
> I get empty files:
>
> str(d2)
> 'data.frame':	0 obs. of  14 variables:
>   \$ V1 : Factor w/ 1 level "9.9761E+11,":
>   \$ V2 : Factor w/ 1 level "threat,":
>   \$ V3 : Factor w/ 96 levels "1,","10,","100,",..:
>   \$ V4 : Factor w/ 2 levels "1,","2,":
>   \$ V5 : Factor w/ 2 levels "1,","2,":
>   \$ V6 : Factor w/ 2 levels "1,","2,":
>   \$ V7 : Factor w/ 2 levels "1,","2,":
>   \$ V8 : Factor w/ 95 levels "abduction,","abortion,",..:
>   \$ V9 : Factor w/ 96 levels "alley,","ankle,",..:
>   \$ V10: Factor w/ 1 level "NA,":
>   \$ V11: Factor w/ 1 level "NA,":
>   \$ V12: Factor w/ 2 levels "203,","205,":
>   \$ V13: Factor w/ 1 level "1,":
>   \$ V14: int
>
> When I use as.integer to change V13 to an integer, the output of this column is replaced by 1s and 2s..
>
>
>> On Apr 21, 2020, at 1:14 AM, Rui Barradas <ruipbarradas using sapo.pt> wrote:
>>
>> Hello,
>>
>> Thanks for the data. But since the replacements still do not work, please post the output of
>>
>>
>>
>> in order for us to have an *exact* copy of the data structure.
>> With a way to exactly reproduce what you have, it will be much easier to try code and find a solution. I, and I believe most R users, will run
>>
>> str(d)
>>
>> as one of the first steps to know what is in that problem column. And go from there.
>>
>>
>> Hope this helps,
>>
>>
>> Às 04:52 de 21/04/20, Helen Sawaya escreveu:
>>> Thank you all for your input.
>>> This is an example of one data file (I have 74 data files):
>>> 2.90546E+11, threat,    1, 2, 1, 2, 1,        death,        stove,            NA,           NA,  205,    0,  394
>>> 2.90546E+11, threat,    2, 2, 2, 1, 1,    emaciated,    shortened,            NA,           NA,  205,    0,  502
>>> 2.90546E+11, threat,    3, 1, 1, 1, 2,     mutilate,     consider,            NA,           NA,  205,    1,  468
>>> 2.90546E+11, threat,    6, 1, 2, 2, 1,         weep,         shop,            NA,           NA,  203,    1,  345
>>> 2.90546E+11, threat,    9, 2, 1, 2, 2,    tormented,    easygoing,            NA,           NA,  205,    1,  373
>>> 2.90546E+11, threat,   10, 1, 2, 2, 2,        snake,        table,            NA,           NA,  205,    1,  343
>>> 2.90546E+11, threat,   11, 2, 2, 1, 1,       crisis,       faucet,            NA,           NA,  203,    1,  437
>>> 2.90546E+11, threat,   12, 1, 1, 1, 1,       victim,      utensil,            NA,           NA,  203,    1,  343
>>> 2.90546E+11, threat,   14, 1, 2, 2, 1,    depressed,    repentant,            NA,           NA,  203,    1,  441
>>> 2.90546E+11, threat,   15, 2, 2, 1, 2,         scum,         shoe,            NA,           NA,  205,    1,  475
>>> ​Column 13 has values of 0s and 1s which my cognitive task outputted. Column 14 is the reaction time (ms) data. I want to get rid of the rows that contain zeros so I thought I'd first replace zeros with NAs then use complete.cases function to get rid of the NAs. I also wanted to apply other functions so I included them all in a loop. All work fine except for the one where I try to turn the zeros to NAs.
>>> Jim when I tried your mockdata example, it worked fine. But when I translated it to my data, I still get zeros in the output. Can you identify any mistranslations I'm doing?
>>> txt.files<-list.files(".",pattern="dotprobe") #all my data files are text files in one folder
>>> for(tf in txt.files) {
>>>    d[,13][d[,13]==0]<-NA #column 13 contains zeros
>>>    d<-d[ ,-c(10,11)] #get rid of columns 10 and 11
>>>    write.table(d,sub("[.]",".tlbs.",tf),quote=FALSE, row.names=FALSE)
>>> }
>>> That's an example of one of the output I get:
>>> V1 V2 V3 V4 V5 V6 V7 V8 V9 V12 V13 V14
>>> 2.90546E+11, threat, 1, 2, 1, 2, 1, death, stove, 205, 0, 394
>>> 2.90546E+11, threat, 2, 2, 2, 1, 1, emaciated, shortened, 205, 0, 502
>>> 2.90546E+11, threat, 3, 1, 1, 1, 2, mutilate, consider, 205, 1, 468
>>> 2.90546E+11, threat, 6, 1, 2, 2, 1, weep, shop, 203, 1, 345
>>> 2.90546E+11, threat, 9, 2, 1, 2, 2, tormented, easygoing, 205, 1, 373
>>> 2.90546E+11, threat, 10, 1, 2, 2, 2, snake, table, 205, 1, 343
>>> Columns 10 and 11 were deleted. But zeros were not replaced by NAs.
>>> After all the data cleaning, the functions I'm interested in including in the loop are: get_tlbs and summarize_bias (and these also work fine in my loop).
>>> Thanks again 🙂
>>> Sincerely
>>> Helen
>>> ------------------------------------------------------------------------
>>> *From:* Jim Lemon <drjimlemon using gmail.com>
>>> *Sent:* Tuesday, April 21, 2020 2:52 AM
>>> *Cc:* Helen Sawaya <helensawaya using hotmail.com>; Michael Dewey <lists using dewey.myzen.co.uk>; r-help using R-project.org <r-help using r-project.org>
>>> *Subject:* Re: [R] NA command in a 'for' loop
>>> Hi Helen,
>>> Your problem may lie in using row.names=TRUE. I was puzzled when an
>>> extra column kept popping up in the output files. For reading in and
>>> replacing zeros with NAs, this seems to work:
>>> for(mockdata in 1:3) {
>>>   mdf<-data.frame(sample(2:20,10),sample(2:20,10),sample(0:1,10,TRUE))
>>>   write.table(mdf,file=paste0("threat",mockdata,".txt"),quote=FALSE,
>>>    row.names=FALSE,col.names=FALSE)
>>> }
>>> txt.files<-list.files(".",pattern="threat[1-3]")
>>> for(tf in txt.files) {
>>>   d[,3][d[,3]==0]<-NA
>>>   write.table(d,sub("[.]",".tbls.",tf),quote=FALSE,row.names=FALSE)
>>> }
>>> Jim
>>> On Tue, Apr 21, 2020 at 7:57 AM Rui Barradas <ruipbarradas using sapo.pt> wrote:
>>>>
>>>> Hello,
>>>>
>>>> I believe the only way we have to see what is happening is for you to
>>>> post the output of
>>>>
>>>>
>>>> dput(head(d, 20))  # or 30
>>>>
>>>>
>>>> or, with d2 a subset of d that includes zeros,
>>>>
>>>>
>>>>
>>>>
>>>> Hope this helps,
>>>>
>>>>
>>>> Às 17:48 de 20/04/20, Helen Sawaya escreveu:
>>>>> I have one column that represents correct response versus error (correct
>>>>> is coded as 1 and error is coded as 0). Nowhere else in the dataset are
>>>>> there values of 0. The vector is treated as an integer.
>>>>> ------------------------------------------------------------------------
>>>>> *From:* Michael Dewey <lists using dewey.myzen.co.uk>
>>>>> *Sent:* Monday, April 20, 2020 7:35 PM
>>>>> *To:* Helen Sawaya <helensawaya using hotmail.com>; Rui Barradas
>>>>> <ruipbarradas using sapo.pt>; r-help using R-project.org <r-help using R-project.org>
>>>>> *Subject:* Re: [R] NA command in a 'for' loop
>>>>> Just a thought Helen but is x being treated as a real and what you think
>>>>> are zero and are printed as zero are in fact some very small number? If
>>>>> so you need to alter your test appropriately.
>>>>>
>>>>> Michael
>>>>>
>>>>> On 20/04/2020 17:25, Helen Sawaya wrote:
>>>>>>
>>>>>> I tried d[] <- lapply(d, function(x) {is.na(x) <- x == 0; x})
>>>>>> but I am still getting zeros instead of NAs in my output..
>>>>>>
>>>>>> I wonder if the problem is that some of my data files don't have any zeros (participants made no errors)..
>>>>>> ________________________________
>>>>>> Sent: Monday, April 20, 2020 9:05 AM
>>>>>> To: Helen Sawaya <helensawaya using hotmail.com>; r-help using R-project.org <r-help using R-project.org>
>>>>>> Subject: Re: [R] NA command in a 'for' loop
>>>>>>
>>>>>> Hello,
>>>>>>
>>>>>>
>>>>>> d[d == 0] <- NA
>>>>>>
>>>>>> try
>>>>>>
>>>>>> d[] <- lapply(d, function(x) {is.na(x) <- x == 0; x})
>>>>>>
>>>>>>
>>>>>> Also, in the first for loop
>>>>>>
>>>>>> paste(i, sep = "")
>>>>>>
>>>>>> does nothing, it's the same as i.
>>>>>> And the same for
>>>>>>
>>>>>> (d2\$V4 == 1) == TRUE
>>>>>>
>>>>>> Since (d2\$V4 == 1)  already is FALSE/TRUE there is no need for
>>>>>>
>>>>>> (.) == TRUE
>>>>>>
>>>>>>
>>>>>> Hope this helps,
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Às 20:52 de 19/04/20, Helen Sawaya escreveu:
>>>>>>> Dear R experts,
>>>>>>>
>>>>>>> I am using a 'for' loop to apply commands to multiple datasets (each file is one participant). The only one not working is the command that identifies zeros in my datasets and changes them to NAs. But when I look at the output, zeros ("0") are still present. Surprisingly, the functions work fine when I apply them to a single
>>>>> dataset (outside the loop). I've tried:
>>>>>>>
>>>>>>> all.files <- list.files(".")
>>>>>>> txt.files <- grep("threat.txt",all.files,value=T)
>>>>>>>
>>>>>>> for(i in txt.files){
>>>>>>>      d[d==0] <- NA #replace zeros with NA
>>>>>>>      write.table(d, paste0(i,".tlbs.txt"), quote=FALSE, row.names=TRUE)}
>>>>>>>      d<-d[ ,-c(10,11)]
>>>>>>>      d2<-d[complete.cases(d), ]
>>>>>>>      d2\$V4<-as.numeric(d2\$V4)
>>>>>>>      congruent <- (d2\$V4 == 1) == TRUE
>>>>>>>      x <- get_tlbs(d2\$V14, congruent, prior_weights = NULL, method = "weighted", fill_gaps = FALSE)
>>>>>>>      write.table(x, paste0(i,".tlbs.txt"), quote=FALSE, row.names=TRUE)}
>>>>>>>
>>>>>>> I've also tried:
>>>>>>>
>>>>>>> for(i in txt.files){
>>>>>>>      if (0 %in% d)
>>>>>>>      {replace_with_na(d,replace = list(x = 0))} # replace zeros with NA
>>>>>>>      d<-d[ ,-c(10,11)]
>>>>>>>      d2<-d[complete.cases(d), ]
>>>>>>>      d2\$V4<-as.numeric(d2\$V4)
>>>>>>>      congruent <- (d2\$V4 == 1) == TRUE
>>>>>>>      x <- get_tlbs(d2\$V14, congruent, prior_weights = NULL, method = "weighted", fill_gaps = FALSE)
>>>>>>>      write.table(x, paste0(i,".summaryoutput.txt"), quote=FALSE, row.names=TRUE)}
>>>>>>>
>>>>>>> Thank you for your help.
>>>>>>> Sincerely
>>>>>>> Helen
>>>>>>>
>>>>>>>          [[alternative HTML version deleted]]
>>>>>>>
>>>>>>> ______________________________________________
>>>>>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>>>
>>>>>>
>>>>>>         [[alternative HTML version deleted]]
>>>>>>
>>>>>> ______________________________________________
>>>>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> Michael
>>>>> http://www.dewey.myzen.co.uk/home.html
>>>>
>>>> ______________________________________________
>>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>> https://stat.ethz.ch/mailman/listinfo/r-help