Narrow down files which names include date to specific months in r-CodePudding

I have thousands of .tif files which contain daily temperature data. The file names include the date in a format like this tminYYYYMMDD.tif, here is a sample:

tmin19810707.tif
tmin19810508.tif
tmin19810314.tif
tmin19810227.tif

I only need the data from June (06), July (07) and August (08) form all those years. How can I select and use for further processing only files that are from those months?

CodePudding user response：

We can use substr for a base R solution:

x <- c("tmin19810707.tif", "tmin19810508.tif", "tmin19810314.tif",
       "tmin19810227.tif")
output <- x[substr(x, 9, 10) %in% c("06", "07", "08")]
output

[1] "tmin19810707.tif"

CodePudding user response：

You can use grep with a regular expression indicating the pattern:

grep("\\D \\d{4}0[6-8]", x, value = TRUE)

[1] "tmin19810707.tif"

x<- c("tmin19810707.tif", "tmin19810508.tif", "tmin19810314.tif", "tmin19810227.tif")

CodePudding user response：

stole the regex from the answer from @onyambu

list.files(path = "./mypath", pattern = "\\D \\d{4}0[6-8].*\\.tif$")