Irregular Time Series: zoo & its: Pros & Cons

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch 
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of David James
Sent: Thursday, August 25, 2005 1:51 PM
To: r-help at stat.math.ethz.ch
Subject: [R] Irregular Time Series: zoo & its: Pros & Cons

Hello,

I'm working with irregular time series data.  What do you all 
think about the strengths and weaknesses of the "zoo" and 
"its" packages?

I've installed and skimmed the documentation on both 
packages.  I was hoping to get a little guidance from the 
user community before proceeding further.

In case anyone is interested in my particular problem:  I'm 
looking at some (surface) temperature data from NOAA:  
http:// cdo.ncdc.noaa.gov/ulcd/ULCD It is (irregular) time 
series format.  The NOAA data reports year, month, date, 
hour, and minute.  I want to group the data into hourly 
chunks.  However, sometimes there are multiple observation per hour
-- i.e an observation at 3:45 and 3:56.  Also, sometimes a 
particular hour may be missing altogether.  I need to clean 
up the data so that each hour has one and only one data point.

I'm relatively new to R, but I think I'm getting a hold on it 
pretty well so far.  I used to do a lot with MATLAB, and 
there seem to be many parallels between it and R.  I have 
background in public policy and econometrics.

Thanks,
David

On Aug 25, 2005, at 12:29 PM, Mathieu Drapeau wrote:

Hi,
I just installed ROracle and RDBI. The connection to the database 
seems to work also. My problem is when I am selection rows 

that really 

exist in the database, it is returning nothing. Where 

should I look to 

see what could be my problem?

Thank you very much,
Mathieu

drv <- dbDriver("Oracle")
summary(drv, verbose=TRUE)

<OraDriver:(6721)>
  Driver name:  Oracle (ProC/C++)
  Max  connections: 10
  Conn. processed: 8
  Default records per fetch: 500
  Oracle R/S client version: 0.5-4
  RS-DBI version:  0.1-9
  Open connections: 2
    1  <OraConnection:(6721,0)>
    2  <OraConnection:(6721,7)>

conn <- dbConnect(drv, "mathieu/toto at MYDB") summary(conn, 
verbose=TRUE) <OraConnection:(6721,7)>

  User: mathieu
  Dbname: MYDB
  Oracle Server version:

rs <- dbSendQuery(conn, statement = paste("select * from cat")) 
summary(rs, verbose=TRUE)

<OraResult:(6721,7,2)>
  Statement: select * from cat
  Has completed? no
  Affected rows: 0
  Rows fetched: -1
  Fields:
        name    Sclass     type len precision scale 

isVarLength nullOK

1 TABLE_NAME character VARCHAR2  30         0     0        

TRUE  FALSE

2 TABLE_TYPE character VARCHAR2  11         0     0        

TRUE   TRUE

myContent <- fetch(rs, n = -1)
myContent

[1] TABLE_NAME TABLE_TYPE
<0 rows> (or 0-length row.names)

summary(myContent, verbose=TRUE)

  TABLE_NAME         TABLE_TYPE
 Length:0           Length:0
 Class :character   Class :character
 Mode  :character   Mode  :character

summary(rs, verbose=TRUE)

<OraResult:(6721,7,2)>
  Statement: select * from cat
  Has completed? yes
  Affected rows: 0
  Rows fetched: -1
  Fields:
        name    Sclass     type len precision scale 

isVarLength nullOK

1 TABLE_NAME character VARCHAR2  30         0     0        

TRUE  FALSE

2 TABLE_TYPE character VARCHAR2  11         0     0        

TRUE   TRUE