One common error you may encounter in R is:
Error in as.POSIXlt.character(x, tz, ...) : character string is not in a standard unambiguous format
This error usually occurs when you attempt to convert an object in R to a date format, but the object is currently either a character or factor.
To fix this error, you must first convert the object to numeric.
This tutorial explains how to fix this error in practice.
How to Reproduce the Error
Suppose we have the following data frame in R:
#create data frame df <- data.frame(date=c('1459397140', '1464397220', '1513467142'), sales=c(140, 199, 243)) #view data frame df date sales 1 1459397140 140 2 1464397220 199 3 1513467142 243
Now suppose we attempt to convert the values in the date column to a date format:
#attempt to convert values in date column to date df$date <- as.POSIXct(df$date, origin='1970-01-01') Error in as.POSIXlt.character(x, tz, ...) : character string is not in a standard unambiguous format
We receive an error because the values in the date column are currently in a character format, which the as.POSIXct() function doesn’t know how to handle.
How to Fix the Error
To fix this error, we need to use as.numeric() to first convert the values in the date column to a numeric format, which is one that as.POSIXct can handle:
#convert values in date column to date df$date <- as.POSIXct(as.numeric(as.character(df$date)), origin='1970-01-01') #view updated data frame df date sales 1 2016-03-31 04:05:40 140 2 2016-05-28 01:00:20 199 3 2017-12-16 23:32:22 243
This time we don’t receive an error and we’re able to successfully convert the values in the date column to a date format because we first converted the values to a numeric format.
The following tutorials explain how to fix other common errors in R: