[R] Why is conversion not working?

[jim holtman]

try this:

> x <- data.frame(month=as.character(sample(1:12,1000,TRUE)),
+     year=as.character(sample(c(0:7, 95:99), 1000, TRUE)),
stringsAsFactors=FALSE)
> # convert to integer
> x$Year <- as.integer(x$year)
> # now add the century
> x$Year <- ifelse(x$Year < 10, x$Year+2000, x$Year+1900)
>
>
> head(x)
  month year Year
1    10   96 1996
2     9    5 2005
3     8   95 1995
4     1    7 2007
5    11    3 2003
6     2   99 1999
>


On Dec 17, 2007 7:52 PM, Jonas Malmros <jonas.malmros at gmail.com> wrote:
> I have a data frame, where two last columns - "month" and "year" - are
> character vectors. The "year" vector is made of two numbers (i.e. "97"
> for 1997, "07" for 2007, etc)
> What I want to do is to create a variable "Year" that is mode numeric
> and where each record is a four-figure number (1997, 2007,...)
> I have about 40000 rows in the dataframe, the observations are for 10
> years (so there are multiple rows for each year).
> I tried the following, but the program runs and runs, and if I abort
> it all the years in "Year" are 1997:
>
> for(i in 1:dim(database)[1]){
>    if(database$year[i]>90) {
>           database$Year[i] <- as.numeric(database$year[i])+1900 } else {
>           database$Year[i] <- as.numeric(database$year[i])+2000
>    }
> }
>
> Thanks in advance for explanations.
>
> Regards,
> JM
>
> --
> Jonas Malmros
> Stockholm University
> Stockholm, Sweden
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?