R help - Jul 2004 - computing differences between consecutive vector elements

Dear R-users,

I am a newbie to R so please excuse this naive question for which I couldn't
seem to find online answers.

I have this data frame containing a series of locations through time
(x,y,z,t). I would like to compute the difference in x, y and z between t-1
and t.

Sounds easy enough, but how on earth does one loop through vector elements
and compute this difference?

Thanks

Thomas
***
Le contenu de cet e-mail et de ses pi??ces jointes est destin?? ?? l'usage
exclusif du
(des) destinataire(s) express??ment d??sign??(s) comme tel(s). En cas de
r??ception de cet
 e-mail par erreur, le signaler ?? son exp??diteur et ne pas en divulguer le
contenu.
L'absence de virus a ??t?? v??rifi?? ??  l'??mission du message. Il
convient n??anmoins de
v??rifier l'absence de corruption ?? sa r??ception.

The contents of this email and any attachments are confidential. They are
intended for
the named recipient(s) only. If you have received this email in error please
notify the
system manager or  the sender immediately and do not disclose the contents to 
anyone or make copies. eSafe scanned this email for viruses, vandals and
malicious
content.
***

Not exactly sure what you want, but seems like you can sort the data frame
by `t', then do diff() on the x, y, and z columns.

Andy
> From: Dewez Thomas
> 
> Dear R-users,
> 
> I am a newbie to R so please excuse this naive question for 
> which I couldn't
> seem to find online answers.
> 
> I have this data frame containing a series of locations through time
> (x,y,z,t). I would like to compute the difference in x, y and 
> z between t-1
> and t.
> 
> Sounds easy enough, but how on earth does one loop through 
> vector elements
> and compute this difference?
> 
> Thanks
> 
> Thomas
> ***
> Le contenu de cet e-mail et de ses pi??ces jointes est destin?? 
> ?? l'usage exclusif du 
> (des) destinataire(s) express??ment d??sign??(s) comme tel(s). 
> En cas de r??ception de cet 
>  e-mail par erreur, le signaler ?? son exp??diteur et ne pas en 
> divulguer le contenu. 
> L'absence de virus a ??t?? v??rifi?? ??  l'??mission du message. Il
> convient n??anmoins de 
> v??rifier l'absence de corruption ?? sa r??ception.
> 
> The contents of this email and any attachments are 
> confidential. They are intended for 
> the named recipient(s) only. If you have received this email 
> in error please notify the 
> system manager or  the sender immediately and do not disclose 
> the contents to 
> anyone or make copies. eSafe scanned this email for viruses, 
> vandals and malicious 
> content.
> ***
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
>

Dewez Thomas wrote:
> Dear R-users,
> 
> I am a newbie to R so please excuse this naive question for which I
couldn't
> seem to find online answers.
> 
> I have this data frame containing a series of locations through time
> (x,y,z,t). I would like to compute the difference in x, y and z between t-1
> and t.
> 
> Sounds easy enough, but how on earth does one loop through vector elements
> and compute this difference?
See ?diff

Hence for a data frame X:
  lapply(X, diff)

Uwe Ligges

> Thanks
> 
> Thomas
> ***
> Le contenu de cet e-mail et de ses pi??ces jointes est destin?? ??
l'usage exclusif du
> (des) destinataire(s) express??ment d??sign??(s) comme tel(s). En cas de
r??ception de cet
>  e-mail par erreur, le signaler ?? son exp??diteur et ne pas en divulguer
le contenu.
> L'absence de virus a ??t?? v??rifi?? ??  l'??mission du message. Il
convient n??anmoins de
> v??rifier l'absence de corruption ?? sa r??ception.
> 
> The contents of this email and any attachments are confidential. They are
intended for
> the named recipient(s) only. If you have received this email in error
please notify the
> system manager or  the sender immediately and do not disclose the contents
to
> anyone or make copies. eSafe scanned this email for viruses, vandals and
malicious
> content.
> ***
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html