R help - Mar 2011 - Trouble with simple R list concatenations

PROBLEM How can I concatenate the following lists into ONE LIST WITHOUT 
the unhelpful message "operator is invalid for atomic vectors"? 
Combine
as a data frame?

EXAMPLE

Birth_Date      <- NULL
Birth_Date[1:3] <- c("01/17/1939","01/17/1949",
"01/17/1959")
Later_Date      <- NULL
Later_Date[1:3] <- c("01/17/2009", NA, NA)
Names           <- NULL
Names[1:3]      <- c("Martha Smith", "John Doe",
"Rufus Nobody")

#this does not work
family          <- c(Birth_Date, Later_Date, Names)
family$Birth_Date
Error in family$Birth_Date : $ operator is invalid for atomic vectors

FUNCTIONALLY DESIRED FROM THE FINAL COMBINED data frame
I would appreciate being able to do the following with the final list or 
data frame.
1. Be able to address names using $
2. Be able to change individual variables like the NA's to a proper date 
perhaps like

family$Later_Date[[3]] <- toString(format(Sys.time(),"%m/%d/%Y"),
width=10)

Thanks, your help would is gratefully accepted,
Jim

First of all, you are working with 'vectors' not 'lists'.  Look
in the
following script what str(family) is on your original input.

What you probably want is a 'data.frame'.  May be time to go back and
re-read the "Intro to R" to understand the differences between
vectors, lists and dataframes.  You may also want to understand what
'factors' are since by default that is what character strings are
converted to in dataframes, and that may not be what you want.
> Birth_Date      <- NULL
> Birth_Date[1:3] <- c("01/17/1939","01/17/1949",
"01/17/1959")
> Later_Date      <- NULL
> Later_Date[1:3] <- c("01/17/2009", NA, NA)
> Names           <- NULL
> Names[1:3]      <- c("Martha Smith", "John Doe",
"Rufus Nobody")
>
> #this does not work
> family          <- c(Birth_Date, Later_Date, Names)
> family$Birth_Date
Error in family$Birth_Date : $ operator is invalid for atomic vectors
No suitable frames for recover()
> str(family)  # notice that this is a character vector of size 9
 chr [1:9] "01/17/1939" "01/17/1949" "01/17/1959"
"01/17/2009" NA NA
"Martha Smith" ...
> family <- data.frame(Birth_Date, Later_Date, Names)
> str(family)
'data.frame':   3 obs. of  3 variables:
 $ Birth_Date: Factor w/ 3 levels
"01/17/1939","01/17/1949",..: 1 2 3
 $ Later_Date: Factor w/ 1 level "01/17/2009": 1 NA NA
 $ Names     : Factor w/ 3 levels "John Doe","Martha
Smith",..: 2 1 3
> family$Birth_Date
[1] 01/17/1939 01/17/1949 01/17/1959
Levels: 01/17/1939 01/17/1949 01/17/1959
>

On Sun, Mar 20, 2011 at 9:32 PM, Jim Burke <j.burke at earthlink.net>
wrote:
> PROBLEM How can I concatenate the following lists into ONE LIST WITHOUT the
> unhelpful message "operator is invalid for atomic vectors"?
?Combine as a
> data frame?
>
> EXAMPLE
>
> Birth_Date ? ? ?<- NULL
> Birth_Date[1:3] <- c("01/17/1939","01/17/1949",
"01/17/1959")
> Later_Date ? ? ?<- NULL
> Later_Date[1:3] <- c("01/17/2009", NA, NA)
> Names ? ? ? ? ? <- NULL
> Names[1:3] ? ? ?<- c("Martha Smith", "John Doe",
"Rufus Nobody")
>
> #this does not work
> family ? ? ? ? ?<- c(Birth_Date, Later_Date, Names)
> family$Birth_Date
> Error in family$Birth_Date : $ operator is invalid for atomic vectors
>
> FUNCTIONALLY DESIRED FROM THE FINAL COMBINED data frame
> I would appreciate being able to do the following with the final list or
> data frame.
> 1. Be able to address names using $
> 2. Be able to change individual variables like the NA's to a proper
date
> perhaps like
>
> family$Later_Date[[3]] <-
toString(format(Sys.time(),"%m/%d/%Y"), width=10)
>
> Thanks, your help would is gratefully accepted,
> Jim
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?