[R] Reading in files with variable parts to names

[baptiste auguie]

Hi,

If your directory contains only files you want to load anyway, then  
list.files() is your friend,

> list.files(pattern = "comp") # or pattern =".asc" for example


If you do need to create the names manually, then you could create the  
combinations with expand.grid, as in,

> do.call(paste, as.list(expand.grid(x = seq(1950,1960), y = 1:10))) #  
> you'll want to tweak paste to suit your needs


HTH,

baptiste

On 26 Mar 2009, at 18:40, Steve Murray wrote:

>
> Dear all,
>
> I'm trying to read in a whole directory of files which have two  
> variable parts to the file name: year and month. E.g. comp198604.asc  
> represents April of 1986 - 'comp' is fixed in each case. Years range  
> between 1986 to 1995 and months are between 1 and 12.
>
> Just to be clear, there are 12 files associated with each year: e.g.  
> comp198601, comp198602, ... comp198612  through to comp199501,  
> comp199502 ... comp199512.
>
> I am trying to automate the reading in of these files, but am  
> struggling to find an adequate way of achieving this. The closest  
> I've got is by doing:
>
>
>
> year <- 1986:1995
> month <- sprintf("%02d", 1:12)  # formats numbers to 2 digits (for  
> maintaining leading zeros in file names)
>
> filelist <- paste("C:\\Documents and Settings\\Data\ 
> \comp",year,month,".asc", sep="")
>
> filelist
>
> [1] "C:\\Documents and Settings\\Data\\comp198601.asc"
> [2] "C:\\Documents and Settings\\Data\\comp198702.asc"
> [3] "C:\\Documents and Settings\\Data\\comp198803.asc"
> [4] "C:\\Documents and Settings\\Data\\comp198904.asc"
> [5] "C:\\Documents and Settings\\Data\\comp199005.asc"
> [6] "C:\\Documents and Settings\\Data\\comp199106.asc"
> [7] "C:\\Documents and Settings\\Data\\comp199207.asc"
> [8] "C:\\Documents and Settings\\Data\\comp199308.asc"
> [9] "C:\\Documents and Settings\\Data\\comp199409.asc"
> [10] "C:\\Documents and Settings\\Data\\comp199510.asc"
> [11] "C:\\Documents and Settings\\Data\\comp198611.asc"
> [12] "C:\\Documents and Settings\\Data\\comp198712.asc"
>
>
> I need 1986 to remain fixed whilst it cycles through 01 to 12,  
> before it moves onto 1987 and cycles again. There should be 120  
> outputs in total (10 years each with 12 months), but at present it's  
> only reaching 12 outputs.
>
> I'd be grateful to learn what I'm doing wrong here so that I can  
> solve this.
>
> Many thanks as ever,
>
> Steve
>
>
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_____________________________

Baptiste Auguié

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag