Hi All,
Petr, Bert, David, Ivan, Duncan and Rui helped me to develop a function
able to replace NA's in variables IF NEEDED:
#-------------------------------------------------------------------------------
# Module : t_replace_na.R
# Author : Georg Maubach
# Date : 2016-06-27
# Update : 2016-06-27
# Description : Replace NA with another value
# Source System : R 3.3.0 (64 Bit)
# Target System : R 3.3.0 (64 Bit)
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#--------1---------2---------3---------4---------5---------6---------7---------8
t_version = "2016-06-27"
t_module_name = "t_replace_na.R"
cat(
paste0("\n",
t_module_name, " (Version: ", t_version, ")", "\n", "\n",
"This software comes with ABSOLUTELY NO WARRANTY.",
"\n", "\n"))
# If do_test is not defined globally define it here locally by
un-commenting it
t_do_test <- FALSE
# [ Function Defintion
]--------------------------------------------------------
t_replace_na <- function(dataset, variables, value) {
# Replace NA with another given value
#
# Args:
# dataset (data frame, data table):
# Object with dimnames, e.g. data frame, data table.
# variables (character vector):
# List of variable names.
#
# Operation:
# NA is replaced by the value given with the parameter "value".
#
# A factor is converted explicitly with as.character(), the missing
value
# replacement is done and then the character vector is converted back
with
# as.factor(). Thus NA becomes a category of the new factor variable.
#
# Caution:
# Please check your data in case you replace NA within factors due to
# explicit type conversion. Tests were done only for the below given
# dataset.
#
# Returns:
# Original dataset.
#
# Error handling:
# None.
#
# Credits:
https://www.mail-archive.com/r-help@r-project.org/msg236537.html
for (variable in variables) {
if (inherits(dataset[, variable], "factor") == TRUE) {
dataset[, variable] <- as.character(dataset[, variable])
print(class(dataset[, variable]))
dataset[, variable][is.na(dataset[, variable])] <- value
dataset[, variable] <- as.factor(dataset[, variable])
print(class(dataset[, variable]))
} else {
dataset[, variable][is.na(dataset[, variable])] <- value
}
}
return(dataset)
}
# [ Test Defintion
]------------------------------------------------------------
t_test <- function(do_test = FALSE) {
if (do_test == TRUE) {
cat("\n", "\n", "Test function t_count_na()", "\n", "\n")
# Example dataset
ds_example <- data.frame(a=c(1,NA,2), b = rep(NA,3), c =
c("A","b",NA))
cat("\n", "\n", "Example dataset before function call", "\n", "\n")
cat("Variables and their classes:\n")
print(sapply(ds_example, class))
cat("Dataset:\n")
print(ds_example)
cat("\n", "\n", "Function call", "\n", "\n")
ds_result <- t_replace_na(ds_example, "a", value = -1)
cat("\n", "\n", "Dataset after function call", "\n", "\n")
print(ds_result)
cat("\n", "\n", "Function call", "\n", "\n")
ds_result <- t_replace_na(ds_example, "b", value = -2)
cat("\n", "\n", "Example dataset after function call", "\n", "\n")
print(ds_result)
cat("\n", "\n", "Function call", "\n", "\n")
ds_result <- t_replace_na(ds_example, "c", value = -3)
cat("\n", "\n", "Example dataset after function call", "\n", "\n")
print(ds_result)
}
}
# [ Test Run
]------------------------------------------------------------------
t_test(do_test = t_do_test)
# [ Clean up
]------------------------------------------------------------------
rm("t_module_name", "t_version", "t_do_test", "t_test")
# EOF .
Please note: R has capabilities to handle NA correctly. There is often no
need to recode NA. Also NA might or might not have meaning. You have to
decide with regard to the meaning of the original data and the business
problem.
Kind regards
Georg
Von: PIKAL Petr <petr.pi...@precheza.cz>
An: "g.maub...@weinwolf.de" <g.maub...@weinwolf.de>,
Kopie: "r-help@r-project.org" <r-help@r-project.org>
Datum: 27.06.2016 11:03
Betreff: RE: [R] Antwort: Fw: Re: Subscripting problem with
is.na()
Hi
see in line
> -----Original Message-----
> From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of
> g.maub...@weinwolf.de
> Sent: Monday, June 27, 2016 10:45 AM
> To: David L Carlson <dcarl...@tamu.edu>; Bert Gunter
> <bgunter.4...@gmail.com>
> Cc: r-help@r-project.org
> Subject: [R] Antwort: Fw: Re: Subscripting problem with is.na()
>
> Hi David,
> Hi Bert,
>
> many thanks for the valuable discussion on NA in R (please see extract
> below). I follow your arguments leaving NA as they are for most of the
> time. In special occasions however I want to replace the NA with another
> value. To preserve the newly acquired knowledge for me I wrote this
> function:
>
> -- cut --
> t_replace_na <- function(dataset, variable, value) {
> if(inherits(dataset[[variable]], "factor") == TRUE) {
> dataset[variable] <- as.character(dataset[variable])
> print(class(dataset[variable]))
> dataset[, variable][is.na(dataset[, variable])] <- value
> dataset[variable] <- as.factor(dataset[variable])
> print(class(dataset[variable]))
> } else {
> dataset[, variable][is.na(dataset[, variable])] <- value
> }
> return(dataset)
> }
>
<snip>
> class(ds_test[, "c"])
> test_class(ds_test, "c")
> warning("'c' should be factor NOT data.frame.
> In addition data.frame != factor")
> -- cut --
>
> Why do I get different results for the same function if it is inside or
> outside my own function definition?
Because you still are missing the way how to subscript data frames.
test_class <- function(dataset, variable) {
if(inherits(dataset[, variable], "factor") == TRUE) {
return(c(class(dataset[,variable]), TRUE))
#### ^^^^
} else {
return(c(class(dataset[,variable]), FALSE))
###### ^^^^
}
}
> test_class(ds_test, "a")
[1] "numeric" "FALSE"
> test_class(ds_test, "c")
[1] "factor" "TRUE"
>
If you properly arrange commas in your function you get desired result
p_replace_na <- function(dataset, variable, value) {
if(inherits(dataset[,variable], "factor") == TRUE) {
dataset[,variable] <- as.character(dataset[,variable])
print(class(dataset[,variable]))
dataset[, variable][is.na(dataset[, variable])] <- value
dataset[, variable] <- as.factor(dataset[, variable])
print(class(dataset[, variable]))
} else {
dataset[, variable][is.na(dataset[, variable])] <- value
}
return(dataset)
}
> p_replace_na(ds_test, "c", value = -3)
[1] "character"
[1] "factor"
a b c
1 1 NA A
2 NA NA b
3 2 NA -3
> t_replace_na(ds_test, "c", value = -3)
[1] "data.frame"
Error in sort.list(y) : 'x' must be atomic for 'sort.list'
Have you called 'sort' on a list?
>
Cheers
Petr
>
> Kind regards
>
> Georg
>
> --------------------------------
>
> > Gesendet: Donnerstag, 23. Juni 2016 um 21:14 Uhr
> > Von: "David L Carlson" <dcarl...@tamu.edu>
> > An: "Bert Gunter" <bgunter.4...@gmail.com>
> > Cc: "R Help" <r-help@r-project.org>
> > Betreff: Re: [R] Subscripting problem with is.na()
> >
> > Good point. I did not think about factors. Also your example raises
> another issue since column c is logical, but gets silently converted to
> numeric. This would seem to get the job done assuming the conversion is
> intended for numeric columns only:
> >
> > > test <- data.frame(a=c(1,NA,2), b = c("A","b",NA), c= rep(NA,3))
> > > sapply(test, class)
> > a b c
> > "numeric" "factor" "logical"
> > > num <- sapply(test, is.numeric)
> > > test[, num][is.na(test[, num])] <- 0
> > > test
> > a b c
> > 1 1 A NA
> > 2 0 b NA
> > 3 2 <NA> NA
> >
> > David C
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.
________________________________
Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou
určeny pouze jeho adresátům.
Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho
kopie vymažte ze svého systému.
Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email
jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi
či zpožděním přenosu e-mailu.
V případě, že je tento e-mail součástí obchodního jednání:
- vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout;
Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany
příjemce s dodatkem či odchylkou.
- trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
výslovným dosažením shody na všech jejích náležitostech.
- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
předloženy nebo jejich existence je adresátovi či osobě jím zastoupené
známá.
This e-mail and any documents attached to it may be confidential and are
intended only for its intended recipients.
If you received this e-mail by mistake, please immediately inform its
sender. Delete the contents of this e-mail with all attachments and its
copies from your system.
If you are not the intended recipient of this e-mail, you are not
authorized to use, disseminate, copy or disclose this e-mail in any
manner.
The sender of this e-mail shall not be liable for any possible damage
caused by modifications of the e-mail or by delay with transfer of the
email.
In case that this e-mail forms part of business dealings:
- the sender reserves the right to end negotiations about entering into a
contract in any time, for any reason, and without stating any reasoning.
- if the e-mail contains an offer, the recipient is entitled to
immediately accept such offer; The sender of this e-mail (offer) excludes
any acceptance of the offer on the part of the recipient containing any
amendment or variation.
- the sender insists on that the respective contract is concluded only
upon an express mutual agreement on all its aspects.
- the sender of this e-mail informs that he/she is not authorized to enter
into any contracts on behalf of the company except for cases in which
he/she is expressly authorized to do so in writing, and such authorization
or power of attorney is submitted to the recipient or the person
represented by the recipient, or the existence of such authorization is
known to the recipient of the person represented by the recipient.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
