[R] How to rename file names with condition

[David Winsemius]

On 7/23/19 6:30 AM, danielmessay--- via R-help wrote:
> Could somebody please help me on this?
>
> I have many files on my computer and would like to change its names so that it would be more meaningful for me. The filenames are in the following format: cvcvcv198307.xlsx
>
> I want to change it in such a way that
> cvcvcv into Domain1983 want to keep it 07 into 3-1 * And here is my main problem (Explanation below).
>
>
> Each month (01-12) is divided into three data points. Meaning,
>
> 01(Jan) has three data points: 1, 2, and 3
> 02(Feb) has the next three data points: 4,5, and 6...12(Dec) will have: 34,35, and 36
>
>
> So, 01 (last digit in my file name) means, first month, first data point, i.e. 1-1
>
>      02 - First month, and second data point, i.e. 1-2
>
>      03 - First month, third data point, i.e 1-3
>
>      04- second month, first data point, i.e. 2-1
>
>      05- 2-2
>
>      06- 2-3
>
>      07 - 3-1
>
>      08 - 3-2
>
>      09 - 3-3
>
>      10 - 4-1
>
>      11 - 4-2
>
>      12 - 4-3
>
>      .
>
>      .
>
>      .
>         35 - 12-2
>         36 - 12-3
>
> And that's all.
>
> I have tried file.rename along with sapply for my whole sets of data
>
> (1:18,000). But i can only manage to change the file names before the last two #digits.
>
> Expected result.
>
> The whole file names changed from
>
>
> cvcvcv198307.xlsx into Domain1983-3-1.txtcvcvcv198414.xlsx into Domain1984-5-2.txt
>
>
>
>
> (Yes, file name extension too!)


It's not clear which area is causing you difficulty. Clearly you need to 
be using `gsub` and the `%/% and `%%` functions: This may help on the 
extraction of the month index and modulo arithmetic:


  test <- c("cvcvcv198301.xlsx", "cvcvcv198302.xlsx", 
"cvcvcv198303.xlsx", "cvcvcv198304.xlsx", "cvcvcv198305.xlsx", 
"cvcvcv198306.xlsx", "cvcvcv198307.xlsx")
  mon <- as.numeric( gsub(".+(\\d{2})\\.xlsx", "\\1",  test) )

  (mon +2) %/% 3
#[1] 1 1 1 2 2 2 3

  (mon +2) %% 3 +1
#[1] 1 2 3 1 2 3 1

You should now have sufficient examples and be able to use `sub` and 
`paste` to modify the file names to suit your requirements.

>
> Thank you guys and I really appreciate any help on this.
> Daniel
>
>
>
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-- 

David.