Error in chartodate x текстовая строка не относится к стандартному однозначному формату

How to deal with the "Error in charToDate(x) : character string is not in a standard unambiguous format" in R - 3 R programming examples

In this R programming post you’ll learn how to fix the “Error in charToDate(x) : character string is not in a standard unambiguous format”.

The content of the post looks as follows:

With that, here’s how to do it!

Example 1: Reproduce the Error in charToDate(x) : character string is not in a standard unambiguous format

In Example 1, I’ll explain how to replicate the “Error in charToDate(x) : character string is not in a standard unambiguous format” when converting character strings to dates in R.

Let’s assume that we want to convert the character string “25 Jan 2025” to the Date class. Then, we might try to apply the as.Date function as shown below:

as.Date("25 Jan 2025")        # Trying to apply as.Date to wrong format
# Error in charToDate(x) : 
#   character string is not in a standard unambiguous format

Unfortunately, the previous R code has returned the error message “Error in charToDate(x) : character string is not in a standard unambiguous format”.

The reason for this error message is that our character string did not have the correct date format.

In the following examples, I’ll show how to solve this problem!

Example 2: Fix the charToDate Error by Changing the Date Format

The following R code shows how to specify the correct format when transforming a character to a date.

If we want to apply the as.Date function properly, we have to use the following date structure:

as.Date("2025-01-25")         # Applying as.Date to correct format
# [1] "2025-01-25"

This time, our code worked flawlessly, and our character string was properly converted to the Date class.

However, this approach might not be useful when dealing with many dates, since it might be too complicated to change all date formats manually.

In the next example, I’ll therefore explain a nice workaround that can be used to transform character strings with the wrong date format.

Example 3: Fix the charToDate Error Using the anydate() Function of the anytime Package

Example 3 explains how to use the anytime package to change character strings to the Date class.

To be able to use the functions of the anytime package, we first have to install and load anytime.

install.packages("anytime")   # Install anytime package
library("anytime")            # Load anytime

Now, we can use the anydate function to convert our original character string from Example 1 to the Date class. The anydate function spots the structure and converts our character string accordingly:

anydate("25 Jan 2025")        # Applying anydate function
# [1] "2025-01-25"

Great!

Video & Further Resources

Would you like to learn more about the debugging of the “Error in charToDate(x) : character string is not in a standard unambiguous format”? Then I recommend watching the following video on my YouTube channel. I explain the contents of this article in the video.

The YouTube video will be added soon.

Furthermore, you may read some of the related articles on this website. I have released several tutorials about related topics such as coding errors, numeric values, counting, and data inspection.

  • predict Error in eval(predvars, data, env) : numeric ‘envir’ arg not of length one
  • Count Number of Words in Character String
  • Find Position of Character in String
  • Get Frequency of Words in Character String
  • Error in as.POSIXlt.character : string not standard unambiguous format
  • Dealing with Error & Warning Messages in R (Overview)
  • Creating Plots in R
  • R Programming Examples

To summarize: At this point you should have learned how to handle the “Error in charToDate(x) : character string is not in a standard unambiguous format” in R programming. In case you have further questions, please let me know in the comments.

Please consider the following

$ R --vanilla

> as.Date("01 Jan 2000")
Error in charToDate(x) :
    character string is not in a standard unambiguous format

But that date clearly is in a standard unambiguous format. Why the error message?

Worse, an ambiguous date is apparently accepted without warning or error and then read incorrectly!

> as.Date("01/01/2000")
[1] "0001-01-20"

I’ve searched and found 28 other questions in the [R] tag containing this error message. All with solutions and workarounds involving specifying the format, iiuc. This question is different in that I’m asking where are the standard unambiguous formats defined anyway, and can they be changed? Does everyone get these messages or is it just me? Perhaps it is locale related?

In other words, is there a better solution than needing to specify the format?

29 questions containing «[R] standard unambiguous format»

> sessionInfo()
R version 2.15.2 (2012-10-26)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_United Kingdom.1252
[2] LC_CTYPE=English_United Kingdom.1252
[3] LC_MONETARY=English_United Kingdom.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_United Kingdom.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

smci's user avatar

smci

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asked Feb 7, 2013 at 15:58

Matt Dowle's user avatar

Matt DowleMatt Dowle

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6

This is documented behavior. From ?as.Date:

format: A character string. If not specified, it will try
‘»%Y-%m-%d»‘ then ‘»%Y/%m/%d»‘ on the first non-‘NA’ element,
and give an error if neither works.

as.Date("01 Jan 2000") yields an error because the format isn’t one of the two listed above. as.Date("01/01/2000") yields an incorrect answer because the date isn’t in one of the two formats listed above.

I take «standard unambiguous» to mean «ISO-8601» (even though as.Date isn’t that strict, as «%m/%d/%Y» isn’t ISO-8601).

If you receive this error, the solution is to specify the format your date (or datetimes) are in, using the formats described in the Details section in ?strptime.

Make sure that the order of the conversion specification as well as any separators correspond exactly with the format of your input string. Also, be sure to use particular care if your data contain day/month names and/or abbreviations, as the conversion will depend on your locale (see the examples in ?strptime and read ?LC_TIME; see also strptime, as.POSIXct and as.Date return unexpected NA).

Henrik's user avatar

Henrik

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answered Feb 7, 2013 at 16:10

Joshua Ulrich's user avatar

Joshua UlrichJoshua Ulrich

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3

In other words, is there a better solution than needing to specify the format?

Yes, there is now (ie in late 2016), thanks to anytime::anydate from the anytime package.

See the following for some examples from above:

R> anydate(c("01 Jan 2000", "01/01/2000", "2015/10/10"))
[1] "2000-01-01" "2000-01-01" "2015-10-10"
R> 

As you said, these are in fact unambiguous and should just work. And via anydate() they do. Without a format.

answered Nov 20, 2016 at 21:32

Dirk Eddelbuettel's user avatar

Dirk EddelbuettelDirk Eddelbuettel

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5

As a complement to @JoshuaUlrich answer, here is the definition of function as.Date.character:

as.Date.character
function (x, format = "", ...) 
{
    charToDate <- function(x) {
        xx <- x[1L]
        if (is.na(xx)) {
            j <- 1L
            while (is.na(xx) && (j <- j + 1L) <= length(x)) xx <- x[j]
            if (is.na(xx)) 
                f <- "%Y-%m-%d"
        }
        if (is.na(xx) || !is.na(strptime(xx, f <- "%Y-%m-%d", 
            tz = "GMT")) || !is.na(strptime(xx, f <- "%Y/%m/%d", 
            tz = "GMT"))) 
            return(strptime(x, f))
        stop("character string is not in a standard unambiguous format")
    }
    res <- if (missing(format)) 
        charToDate(x)
    else strptime(x, format, tz = "GMT")
    as.Date(res)
}
<bytecode: 0x265b0ec>
<environment: namespace:base>

So basically if both strptime(x, format="%Y-%m-%d") and strptime(x, format="%Y/%m/%d") throws an NA it is considered ambiguous and if not unambiguous.

answered Feb 7, 2013 at 16:19

plannapus's user avatar

Converting the date without specifying the current format can bring this error to you easily.

Here is an example:

sdate <- "2015.10.10"

Convert without specifying the Format:

date <- as.Date(sdate4) # ==> This will generate the same error"""Error in charToDate(x): character string is not in a standard unambiguous format""".

Convert with specified Format:

date <- as.Date(sdate4, format = "%Y.%m.%d") # ==> Error Free Date Conversion.

Tunaki's user avatar

Tunaki

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answered Dec 19, 2015 at 20:42

HassanSh__3571619's user avatar

0

This works perfectly for me, not matter how the date was coded previously.

library(lubridate)
data$created_date1 <- mdy_hm(data$created_at)
data$created_date1 <- as.Date(data$created_date1)

answered Jun 7, 2019 at 0:56

Viviana Wu's user avatar

As a complement:
This error can be raised as well if an entry you are trying to cast is a string that should have been NA. If you specify the expected format -or use «real» NAs- there are no problems:

Minimum reproducible example with data.table:

library(data.table)
df <- data.table(date_good = c("01-01-2001", "01-01-2001"), date_bad= ("NA", "01-01-2001"))

df[, .(date_good = as.Date(date_good), date_bad = as.Date(date_bad))]
# Error in charToDate(x) : character string is not in a standard unambiguous format

df[, .(date_good = as.Date(date_good), date_bad = as.Date(date_bad, format="%Y-%m-%d"))]
# No errors; you simply get NA.

df2 <- data.table(date_good = c("01-01-2001", "01-01-2001"), date_bad= (NA, "01-01-2001"))
    
df2[, .(date_good = as.Date(date_good), date_bad = as.Date(date_bad))]
# Just NA

answered Aug 4, 2021 at 21:13

Semiramis C's user avatar

1

If the date is for example: «01 Jan 2000», I recommend using

library(lubridate)
date_corrected<-dmy("01 Jan 2000")
date_corrected
[1] "2000-01-01"
class(date_corrected)
[1] "Date"

lubridate has a function for almost every type of date.

answered Jul 12, 2021 at 20:55

Cindy Carolina Lugo Rozo's user avatar

Have been using the package quite happily until today it spits out this error message:

  Error in charToDate(x) : character string is not in a standard unambiguous format

I’m looping over several accounts to rollup the data, with the same start and end date, so not sure why this occurs for only one fetch…..

ah, I see now it is when I include the «ga:date» dimension in the fetch.

i.e.

 dimensions = 'ga:campaign,ga:adGroup,ga:transactionId' 

runs successfully but:

    dimensions = 'ga:date,ga:campaign,ga:adGroup,ga:transactionId'

…triggers the error message on some of the profiles (I suspect empty result ones) and breaks the loop.

I have also wrapped the GA data call to a try() command, so I’m not sure why this error breaks the loop — am I not catching all the errors correctly? I put this in to get around the 0 results that have occured before:

for (i in 1:length(GAProfileTable$id)) {

print(paste("Fetching:",GAProfileTable$name[i],
            "ProfileID:",GAProfileTable$id[i], 
            start_date, end_date, metrics, dimensions,
            "sort:", sort,"filters:",filters, "segment:",segment))
# If max is -1, then no limit on max and it will get all results
if (max_results<0) {
  GA.data <- try(ga$getData(GAProfileTable$id[i], batch = TRUE, start.date = start_date, end.date = end_date, 
                          metrics = metrics, dimensions = dimensions, 
                          sort = sort, filters = filters, segment = segment,
                          start = start_index), silent = TRUE)
} else {      #otherwise it will get max results.
  GA.data <- try(ga$getData(GAProfileTable$id[i], batch = TRUE, start.date = start_date, end.date = end_date, 
                          metrics = metrics, dimensions = dimensions, 
                          sort = sort, filters = filters, segment = segment,
                          start = start_index, max = max_results), silent = TRUE)

}

      #if error, class is "try-error"
      if (class(GA.data) != "try-error"){
        print("Fetch Successful, writing")
        GA.data$name <- GAProfileTable$name[i]
        GA.data$currency <- GAProfileTable$currency[i]
        Results <- rbind(Results,GA.data)
      } else {
        ErrorMessage <- paste("WARK WARK ERROR WITH GAProfileTable$id = ",
                              GAProfileTable$id[i],
                              "name:",
                              GAProfileTable$name[i])
        Results <- rbind(Results,GA.data)
        print(ErrorMessage)
        print(GA.data)
      }    

}

…but perhaps that helps narrow it down?

For a time series analysis of over 1000 raster in a raster stack I need the date. The data is almost weekly in the structure of the files
«… 1981036 …. tif»
The zero separates year and week
I need something like: «1981-36»

but always get the error
Error in charToDate (x): character string is not in a standard unambiguous format

library(sp)
library(lubridate)
library(raster)
library(Zoo)

raster_path <- ".../AVHRR_All"
all_raster <- list.files(raster_path,full.names = TRUE,pattern = ".tif$")
all_raster

brings me:
all_raster

".../VHP.G04.C07.NC.P1981036.SM.SMN.Andes.tif"
".../VHP.G04.C07.NC.P1981037.SM.SMN.Andes.tif"
".../VHP.G04.C07.NC.P1981038.SM.SMN.Andes.tif"
…

To get the year and the associated week, I have used the following code:

timeline <- data.frame(
  year= as.numeric(substr(basename(all_raster), start = 17, stop = 17+3)),
  week= as.numeric(substr(basename(all_raster), 21, 21+2))
)
timeline

brings me:
timeline

     year week
1    1981   35
2    1981   36
3    1981   37
4    1981   38
…

But I need something like = «1981-35» to be able to plot my time series later

I tried that:

timeline$week <- as.Date(paste0(timeline$year, "%Y")) + week(timeline$week -1, "%U")

and get the error:Error in charToDate(x) : character string is not in a standard unambiguous format

or I tried that

fileDates <- as.POSIXct(substr((all_raster),17,23), format="%y0%U")

and get the same error

For a time series analysis of over 1000 raster in a raster stack I need the date. The data is almost weekly in the structure of the files
«… 1981036 …. tif»
The zero separates year and week
I need something like: «1981-36»

but always get the error
Error in charToDate (x): character string is not in a standard unambiguous format

library(sp)
library(lubridate)
library(raster)
library(Zoo)

raster_path <- ".../AVHRR_All"
all_raster <- list.files(raster_path,full.names = TRUE,pattern = ".tif$")
all_raster

brings me:
all_raster

".../VHP.G04.C07.NC.P1981036.SM.SMN.Andes.tif"
".../VHP.G04.C07.NC.P1981037.SM.SMN.Andes.tif"
".../VHP.G04.C07.NC.P1981038.SM.SMN.Andes.tif"
…

To get the year and the associated week, I have used the following code:

timeline <- data.frame(
  year= as.numeric(substr(basename(all_raster), start = 17, stop = 17+3)),
  week= as.numeric(substr(basename(all_raster), 21, 21+2))
)
timeline

brings me:
timeline

     year week
1    1981   35
2    1981   36
3    1981   37
4    1981   38
…

But I need something like = «1981-35» to be able to plot my time series later

I tried that:

timeline$week <- as.Date(paste0(timeline$year, "%Y")) + week(timeline$week -1, "%U")

and get the error:Error in charToDate(x) : character string is not in a standard unambiguous format

or I tried that

fileDates <- as.POSIXct(substr((all_raster),17,23), format="%y0%U")

and get the same error

I am working with data in R that I imported form excel format.

I have a column (isas1_3b) in the dataframe (LPAv1.1.1) which is in the character format. Upon importing, the dates have changed from the format dd/mm/yy, to days (e.g., 41268).

I have tried to convert this as below:

as.Date(LPAv1.1.1$isas1_3b, origin = "1899-12-30")

However, I get the following error:

Error in charToDate(x) : character string is not in a standard unambiguous format
4. stop(«character string is not in a standard unambiguous format»)
3. charToDate(x)
2. as.Date.character(LPAv1.1.1$isas1_3b, origin = «1899-12-30»)
1. as.Date(LPAv1.1.1$isas1_3b, origin = «1899-12-30»)

I’m not sure what I am doing wrong. After numerous searches, the above conversion is what was recommended.

I should also add, that there are two other date columns in the original excel document. But they have both been read in as 'POSIXct''POSIXt'.

Other info that may be relevant:

macOS 13.13.3 R 3.3.3 RStudio 1.1.419

Can someone please help resolve this issue… I am assuming it is something that I am doing. Please let me know if you need any more info.

I am working with data in R that I imported form excel format.

I have a column (isas1_3b) in the dataframe (LPAv1.1.1) which is in the character format. Upon importing, the dates have changed from the format dd/mm/yy, to days (e.g., 41268).

I have tried to convert this as below:

as.Date(LPAv1.1.1$isas1_3b, origin = "1899-12-30")

However, I get the following error:

Error in charToDate(x) : character string is not in a standard unambiguous format
4. stop(«character string is not in a standard unambiguous format»)
3. charToDate(x)
2. as.Date.character(LPAv1.1.1$isas1_3b, origin = «1899-12-30»)
1. as.Date(LPAv1.1.1$isas1_3b, origin = «1899-12-30»)

I’m not sure what I am doing wrong. After numerous searches, the above conversion is what was recommended.

I should also add, that there are two other date columns in the original excel document. But they have both been read in as 'POSIXct''POSIXt'.

Other info that may be relevant:

macOS 13.13.3 R 3.3.3 RStudio 1.1.419

Can someone please help resolve this issue… I am assuming it is something that I am doing. Please let me know if you need any more info.

У меня есть данные о дате, и я хочу извлечь название месяца и его год:

>head(merged.tables$Date)

 2015-07-31
 2013-01-12
 2014-01-03
 2014-12-03
 2013-11-13
 2013-10-27

Другими словами, мне нужно получить результат, расположенный в порядке возрастания следующим образом:

January_2013
 October_2013
 November_2013
 January_2014
 December_2014
 July_2015

Поэтому я попытался использовать этот код для первого преобразования, как показано в приведенном выше коде.

merged.tables$Date <-paste(months(as.Date(merged.tables$Date)),year(as.Date(merged.tables$Date)),sep="_")

Но он показывает мне эту ошибку:

Ошибка в charToDate (x): символьная строка не в стандартном однозначном формате

Я попытался адаптировать это решение символьная строка не входит в стандартную однозначную формат. Но я не могу это решить!

Спасибо за вашу помощь

2 ответа

Лучший ответ

Вы можете использовать order в исходных датах, чтобы получить правильный порядок.
Сначала прочтите свой пример данных.

Date <- scan(what = character(), text = '
2015-07-31
 2013-01-12
 2014-01-03
 2014-12-03
 2013-11-13
 2013-10-27')
Date <- as.Date(Date)

Теперь переформатируйте и упорядочите их.

inx <- order(Date)
newDate <- format(Date, format = "%B_%Y")[inx]
newDate
#[1] "January_2013"  "October_2013"  "November_2013" "January_2014" 
#[5] "December_2014" "July_2015"

Обратите внимание, что это предполагает, что даты относятся к классу Date.


0

Rui Barradas
15 Фев 2018 в 16:15

Попробуйте это (передав свою дату персонажу):

merged.tables$Date <-paste(months(as.Date(as.character(merged.tables$Date))),year(as.Date(as.character(merged.tables$Date))),sep="_")

Если вы создадите свой data.frame таким образом, у вас не будет этой ошибки:

merged.tables<-data.frame(Date=c("2015-07-31","2013-01-12",
"2014-01-03",
"2014-12-03",
"2013-11-13",
"2013-10-27"))

Я предполагаю, что проблема связана с классом ваших данных.

Заказ:

merged.tables$Date2 <-paste(months(as.Date(as.character(merged.tables$Date))),year(as.Date(as.character(merged.tables$Date))),sep="_")

merged.tables[order(merged.tables$Date),]
        Date         Date2
2 2013-01-12  gennaio_2013
6 2013-10-27  ottobre_2013
5 2013-11-13 novembre_2013
3 2014-01-03  gennaio_2014
4 2014-12-03 dicembre_2014
1 2015-07-31   luglio_2015


0

Terru_theTerror
15 Фев 2018 в 16:22

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