041_change_file_name_EXAMPLE.R

TODO

2024-04-08
-   put into function;
-   add tmp dir and tests?

##  EXAMPLE:   if file name is of form dddd and lead d is 0, cut it.   ie  0123 becomes 123;  but 4123 is left alone

# -----------------
#   current setup
# -----------------
# dir <- "~/code/try_things_here/BASE/"
#dir <- "~/code/try_things_here/envir/"
dir  <-  "~/code/mp3/"
list.files(dir)

# ------------------------------------------------
#   files to be changed (0 followed by 4 digits)
# ------------------------------------------------
pat <- "^0[0-9]{3}"
# L= list.files(dir, pattern = pat, full.names=T)
L <- list.files(dir, pattern = pat)
L

# ----------------------------------------------------------------------
#   for each such file, make this change (here:  remove leading  zero)
# ----------------------------------------------------------------------
pat <- "^0"
M <- gsub(x = L, pattern = pat, replacement = "")
M

# ------------------------
#   add directory prefix
# ------------------------
L1 <- paste0(dir, L) # OLD list
M1 <- paste0(dir, M) # NEW list

# ---------------------------------------------------
# double check!  L1 should be OLD list, M1 should be NEW list
# ---------------------------------------------------
L1
M1

# ------------------------
#* file.rename(old, new)
# ------------------------
file.rename(L1, M1)
list.files(dir)