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?