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.

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Approach 1: Error in character string is not in a standard unambiguous format

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!

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