Regex - replace folder details with filename - regex

Question

Completely new to Regex so I was hoping I could find an answer here.
I'm using Notepad++, and I have a big bulk of file details from a folder in a text document, like so:
01/01/2015 08:00 1,000,000 filename.exe
01/02/2015 08:30 1,450,000 aDifferentFilename.exe
And I want to do a find and replace so that the whole thing is replaced by:
filename.exe
aDifferentFilename.exe
I could delete them manually, but there's over a thousand lines!
I've used ^(.*)% to find the lines one by one, but what would I put in the replace field to keep the filename, i.e filename.exe?
Any help/explanation would be great!

Answer 1

In Notepad++'s find dialog, click on the tab for "replace" (probably obvious, but to be complete). Make sure the radio button for "Regular expression" is checked (again, probably obvious). In the "Find what:" text box enter:
^([^ ]+[ ]+){3}(.*)$
if the pattern in your file is consistently four total fields of information (including the file names) each separated by spaces. Explanation: finds three groups of one or more non spaces followed by one or more spaces followed by everything else on the line. "Everything else on the line" is assigned to group 2 (it is enclosed in the second set of parenthesis the expression). We will use this fact below to specify the "Replace with:" string. This is necessary to advance the search position past the text we want to keep, otherwise after the replacement it would match the expression, and would itself be replaced.
Enter this:
^(.{34})(.*)$
if the consistent pattern in your file is that the file name always starts in the 35th column (both patterns could hold true, in which case you could use either). Explanation: This finds the first 34 characters at the start of each line followed by everything else on the line. See explanation above why we want to "find everything else on the line." Note that it is not necessary to group ".{34}" in parenthesis, I simply did this so that in both exampls the "replace with:" text would be group 2.
In the "Replace with:" text box enter \2
Explanation: This tells Notepad++ to replace what we matched with the group 2 subset of what we matched, in other words, "everything else on the line", which in this case is the file name.
Click "Replace"
Another option: If the text you want to keep always starts in column 35 (like required for the approach immediately above), you can select the column of text you want to delete by holding down ctrl+alt+shift and then left clicking with your mouse and dragging. Once the text is selected, hit delete

Answer 2

You can try matching on either 3 sets of spaces, or assume the comma is always fixed. Here is something quick and dirty which matches the comma in a greedy fashion, and 5 characters after that.
^(.*,.....)