Error in chartodate x character string is not in a standard unambiguous format

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.

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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?

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Error in character string is not in a standard unambiguous format is described in this article.

Let us take an example.

date <- "3458745875"                        
date                                               
"3458745875"

The structure of our example data is shown in the previous RStudio console output: It’s a single date object with a numeric format.

Minimum number of units in an Experimental Design »

Let’s pretend we’re trying to convert a numerical date to a regular date object. Then, as demonstrated below, we may try using the as.POSIXct function.

as.POSIXct(date, origin = "1984-01-01")
Error in as.POSIXlt.character(x, tz, ...) :
character string is not in a standard unambiguous format

It’s worth noting that if we used the as.POSIXct function on a factor, we’d get a similar error notice.

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Approach 2: Fix Error in as.POSIXlt.character(x, tz, …) : character string is not in a standard unambiguous format

The date, which is currently formatted as a character, must first be converted to the numeric class.

date <- as.numeric(as.character(date)) 
date
3458745875

Now let’s try,

as.POSIXct(date, origin = "1984-01-01")
"2093-08-08 00:14:35 IST"

This is completely functional!

Linear optimization using R » Optimal Solution »

The post Error in character string is not in a standard unambiguous format appeared first on finnstats.

Error messages are a major nuisance to programmers. In fact, if you are not getting error messages you are probably not doing any programming. They can often occur when changing date formats. The character string is not in a standard unambiguous format error message is an easy one to get but even easier to fix.

Description Of The Problem

The character string is not in a standard unambiguous format is a problem that can occur when changing date format using the posixct function. It occurs when converting numeric dates to calendar dates. It is not a problem caused by leading zeros but by using the wrong format in your numeric date. This is why this type of error can be quite tricky. The key to understanding this error is the fact that the numeric date must be a number and not a string. Once you understand this simple detail, you will be able to avoid this problem completely.

Explanation Of The Error

The problem leading to this problem is that the posixct function is looking for a numeric value in the date argument. This error results when you try to enter a character string instead. It will not accept a missing value, but the date variable will round off a decimal number. The function is trying to use the data to calculate calendar dates.

> dates = “1004623500”
> dates
[1] “1004623500”
> as.POSIXct(dates, origin = “1984-01-01”)
Error in as.POSIXlt.character(x, tz, …) :
character string is not in a standard unambiguous formatt

In this example of a situation that causes the problem, you can plainly see that the date variable is being equated to a string and not a number. As a result of this problem, the formula spits out this message.

How To Fix The Problem.

Fixing this problem is quite easy, all that is necessary is to change the input of the date variable as seen below.

> dates = 1004623500
> dates
[1] 1004623500
> as.POSIXct(dates, origin = “1984-01-01”)
[1] “2015-11-01 09:05:00 EST”

As you can see this version produces a date and time. Now if you do not like the format, you can always change it using the strptime or strftime functions. You can also store it in a data frame, character vector, a json file or several other object types. As you can see the results produce a string representation of the day and time although it does not give either daymonth names or month names. There is also no way of encoding dates in byte or Unicode format.

This is an extremely easy problem to avoid, but it is also one that is easy to fall into. To avoid making this mistake it is important to keep in mind that the numerical date needs to be a numerical value. Keep this one fact in mind and you will avoid this problem.

I am writing because I have nowhere else to go to get an answer. I am trying to shrink my existing table a bit. It is of the next form:

Živilec;     Proizvodnja;            Kariera d.o.o.;  18.11.2014 hh.mm.ss;  Ljubljana
Živilec;     Prehrambena industrija; Kariera d.o.o.;  18.11.2014 hh.mm.ss;  Ljubljana
Vodja;       Strojništvo;            Adecco;          18.11.2014 hh.mm.ss;  Maribor
Vodja;       Tehnične storitve;      Adecco;          18.11.2014 hh.mm.ss;  Maribor
Vodja;       Elektrotehnika;         Adecco;          18.11.2014 hh.mm.ss;  Celje

, the dates are actually inserted as 18.11.2014 8:35:59 but I dont need the time, just the date.
And what I wish to get to is this:

Živilec;  Proizvodnja,Preh. industrija; Kariera d.o.o.; 18.11.2014;          Ljubljana
Vodja;    Stroj.,Teh. stor., Elektro.;  Adecco;         18.11.2014;          Maribor, Celje

I have tryed getting this with the help of this R-code:

matrik<-matrix(0,600,30)
for (i in 1:dim(a)[1]){
  if (is.element(a[i,3],matrik[,15])==TRUE & is.element(a[i,1],matrik[,1])==TRUE){
    katero<-which(a[i,1]==matrik[,1])
    kdo<-which(a[i,15]==matrik[,15])
    kje<-min(intersect(kdo,katero))
    if (kje!=0){
      prosto<-min(which(matrik[kje,2:14]==0))
      matrik[kje,prosto]<-as.character(a[i,2])
      prosti<-min(which(matrik[kje,17:30]==0))
      matrik[kje,prosti]<-as.character(a[i,5])
    }
    if (kje==0){
      povrsti<-min(which(matrik[,1]==0))
      matrik[povrsti,1]<-as.character(a[i,1])
      prosto<-min(which(matrik[povrsti,2:14]==0))+1
      matrik[povrsti,prosto]<-as.character(a[i,2])
      matrik[povrsti,15]<-as.character(a[i,3])
      matrik[povrsti,16]<-as.character(a[i,4])
      prosti<-min(which(matrik[povrsti,17:30]==0))+1
      matrik[povrsti,prosti]<-as.character(a[i,5])      
    }
  }
  else {
    povrsti<-min(which(matrik[,1]==0))
    matrik[povrsti,1]<-as.character(a[i,1])
    prosto<-min(which(matrik[povrsti,2:14]==0))+1
    matrik[povrsti,prosto]<-as.character(a[i,2])
    matrik[povrsti,15]<-as.character(a[i,3])
    matrik[povrsti,16]<-as.character(a[i,4])
    prosti<-min(which(matrik[povrsti,17:30]==0))+16
    matrik[povrsti,prosti]<-as.character(a[i,5])  
  }

}

Basically I make a new matrix in which I will store the values, because i cannot store the categories like teh. storitve, strojništvo, elektro in one cell and just 2 values in another cell in the same column I decided to look at the maximum value of all the categories and make that many cells. If this problem is solvable otherwise please let me know aswell if you could. So anyways after making a zero matrix, I check if the first element (so «Živilec») and the third element (so «Kariera d.o.o.) are the same, if that is true I would like to just add values to the second and fifth(last) column. If not I see that I must add a new row to the existing matrix with all the values from the table. As I run this code I get the error:

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

What to do? Any solutions?

Thank you for your time.

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