# How to extract time using R from MATLAB serial date number?

I have a MATLAB serial number that I need to use in R, but I need to convert them to a normal date.

```
Matlab:
datestr(733038.6)
ans =
27-Dec-2006 14:24:00
```

you can see that it gives the date and time.

```
Now we try in R:
Matlab2Rdate <- function(val) as.Date(val - 1, origin = '0000-01-01')
> Matlab2Rdate(733038.6)
[1] "2006-12-27"
```

It only gives the date, but I need the time as well? Any idea

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1 answer

The Matlab trick is using "Jan 01, 0000", a fictitious reference date, to calculate its date number. The origin of the time for the "POSIXct" class in R is: "1970-01-01 00: 00.00 UTC. You can read about how different systems handle dates here .

Before converting, you need to account for this difference in the link from one format to another. This example contains the POSIX manual . Here's my output:

```
> val<-733038.6
> as.POSIXct((val - 719529)*86400, origin = "1970-01-01", tz = "UTC")
[1] "2006-12-27 14:23:59 UTC"
```

Where 719529 is 1970-01-01 00: 00.00 UTC in the Matlab tree structure and 86400 is the number of seconds in UTC standard time.

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