R list files with multiple conditions

问题

I want to list all files in a directory that met certain conditions (date and currency). So with only one condition the argument pattern in list.files works well:

    file.ls <- list.files(path='~/DATA/PiP/Curvas/',pattern='20130801')

For multiple conditions I've tried:

    file.ls <- list.files(path='~/DATA/PiP/Curvas/',pattern=c('20130801','USD'))

But had the same result as the first one. Is there a way to have multiple criteria in pattern argument of list.files?

回答1:

 Filter(function(x) grepl("USD", x), file.ls)

alternatively, you could construct a regular expression for pattern that only matches filenames containing both strings, but that's a wizard's game.

回答2:

file.ls <- list.files(path='~/DATA/PiP/Curvas/',pattern="20130801|USD")

回答3:

In line with Baptiste and the answer on this post (list.files pattern argument in R, extended regular expression use), you can use the following expression:

file.ls <- list.files(path='~/DATA/PiP/Curvas/',
pattern=glob2rx("*20130801*USD*"))

Where * is the wildcard.

回答4:

Here it is:

file.ls2 = intersect(list.files(pattern = "20130801"), list.files(pattern = "USD"))

来源：https://stackoverflow.com/questions/18028225/r-list-files-with-multiple-conditions