Dear user,

Here some thoughts about using the action command FileList as alternative to FileExists.

Suppose, my music folder contains several files such as

Bach-BWV545.mp3
Bach-BWV563.mp3
Bach-BWV564.mp4

Suppose further, that we make a VisualNeo Win program that checks if a specific file exists.
For this task, VisualNeo has the action command FileExists:

SetVar "[File]" "Bach-BWV545.mp3"
FileExists "[PubDir][File]" "[ReturnValue]"
If "[ReturnValue]" "=" "True"
  AlertBox "Status" "The file [File] was found in the folder [PubDir]."
EndIf

We could also use the command FileList:

SetVar "[File]" "Bach-BWV545.mp3"
FileList "[PubDir][File]" "Files" "[ReturnValue]"
If "[ReturnValue]" "=" "[File]"
  AlertBox "Status" "The file [ReturnValue] was found in the folder [PubDir]."
EndIf

Notice that FileList returns the variable [ReturnValue], that contains the filename if the file exists (here: Bach-BWV545.mp3).
If the file is not found, then the variable [ReturnValue] is empty.

FileList has even more to offer thanks to the wildcard characters * and ? and []

1. Wildcard character *

* matches any character zero or more times.
To check if a specific file exists and only knowing an unique part of the filename (here the number after BWV), use:

SetVar "[PartFileName]" "545"
FileList "[PubDir]*[PartFileName]*" "Files" "[ReturnValue]"
If "[ReturnValue]" "<>" ""
  AlertBox "Status" "The file [ReturnValue] was found in the folder [PubDir]."
EndIf

2. Wildcard character ?

? matches a single character.
To check if a specific file exists but not knowing if the file has the extension mp3 or mp4, use:

SetVar "[PartExtensionFileName]" ".mp?"
FileList "[PubDir]BWV564.[PartExtensionFileName]" "Files" "[ReturnValue]"
If "[ReturnValue]" "<>" ""
  AlertBox "Status" "The file [ReturnValue] was found in the folder [PubDir]."
EndIf

3a. Brackets []

Use brackets [ and ] to look for any of the characters between the brackets. The previous example could be improved:

SetVar "[PartExtensionFileName]" ".mp[#91]34[#93]"

Now the so called character class or character set [34] matches 3 and 4. In this case .mp3 and .mp4 are matched.
Notice the use of [#91] and [#93] in SetVar: these ASCII values for the brackets [ and ] are necessary to have the job done.

A dash between two characters suggests a range of value:

SetVar "[PartFileName]" "B[#91]a-e[#93]ch*"

matches a filename that starts with the string Bach, Bbch, Bcch, Bdch or Bech.

3b. ! in Brackets []

An exclamation mark prevents matching any of the characters between the brackets.

SetVar "[PartFileName]" "B[#91]!a[#93]ch*"
FileList "[PubDir]*[PartFileName]*" "Files" "[ReturnValue]"

The variable [ReturnValue] will now be empty.

Conclusion

Till now I used FileList in two ways (what seems a common practice looking at posts on https://archive.visualneo.com):

1. To generate a list of all files: FileList “[PubDir]*.*” “Files” “[ReturnValue]”
2. To generate a list of files with a specific extension like .txt: FileList “[PubDir]*.txt” “Files” “[ReturnValue]”

Since last week I use FileList as an alternative to FileExists if only parts of a filename are known, using the characters *, ? and [] – the latter whether or not with the exclamation mark !

Best regards,
Reinier