I need to use the strptime function to convert timestamps which look like the following:
Tue Feb 11 12:18:36 +0000 2014
Tue Feb 11 12:23:22 +0000 2014
Tue Feb 11 12:26:26 +0000 2014
Tue Feb 11 12:28:02 +0000 2014
As required, I have copied this into a csv file and read it into R:
timestamp_data <- read.table('timestamp_data.csv')
I then tried to convert it to recognized times using:
timestamp_data_formatted <- strptime(timestamp_data[,1], format ="%a %b %d %H:%M:%S %z %Y")
I still get NA values when I try and view the formatted data in R. I think the problem is that when I view my imported csv data in R, instead of showing '+0000' it simply shows 0. How can I fix this?
You're using read.table, not read.csv. The former splits on whitespace and thus is splitting the datetimes into multiple columns:
df <- read.table(text = 'Tue Feb 11 12:18:36 +0000 2014
Tue Feb 11 12:23:22 +0000 2014
Tue Feb 11 12:26:26 +0000 2014
Tue Feb 11 12:28:02 +0000 2014')
df
#> V1 V2 V3 V4 V5 V6
#> 1 Tue Feb 11 12:18:36 0 2014
#> 2 Tue Feb 11 12:23:22 0 2014
#> 3 Tue Feb 11 12:26:26 0 2014
#> 4 Tue Feb 11 12:28:02 0 2014
str(df)
#> 'data.frame': 4 obs. of 6 variables:
#> $ V1: Factor w/ 1 level "Tue": 1 1 1 1
#> $ V2: Factor w/ 1 level "Feb": 1 1 1 1
#> $ V3: int 11 11 11 11
#> $ V4: Factor w/ 4 levels "12:18:36","12:23:22",..: 1 2 3 4
#> $ V5: int 0 0 0 0
#> $ V6: int 2014 2014 2014 2014
If you use read.csv (with sensible arguments), it works:
df <- read.csv(text = 'Tue Feb 11 12:18:36 +0000 2014
Tue Feb 11 12:23:22 +0000 2014
Tue Feb 11 12:26:26 +0000 2014
Tue Feb 11 12:28:02 +0000 2014', header = FALSE, stringsAsFactors = FALSE)
df$datetime <- as.POSIXct(df$V1, format = '%a %b %d %H:%M:%S %z %Y', tz = 'UTC')
df
#> V1 datetime
#> 1 Tue Feb 11 12:18:36 +0000 2014 2014-02-11 12:18:36
#> 2 Tue Feb 11 12:23:22 +0000 2014 2014-02-11 12:23:22
#> 3 Tue Feb 11 12:26:26 +0000 2014 2014-02-11 12:26:26
#> 4 Tue Feb 11 12:28:02 +0000 2014 2014-02-11 12:28:02
str(df)
#> 'data.frame': 4 obs. of 2 variables:
#> $ V1 : chr "Tue Feb 11 12:18:36 +0000 2014" "Tue Feb 11 12:23:22 +0000 2014" "Tue Feb 11 12:26:26 +0000 2014" "Tue Feb 11 12:28:02 +0000 2014"
#> $ datetime: POSIXct, format: "2014-02-11 12:18:36" "2014-02-11 12:23:22" ...
I'm using as.POSIXct here instead of strptime because the former is usually what you'll need, but strptime works now, too.