Add new parameter --input-file-filter

This lets the user filter the files in the input directory by a regex

Validation/src/Validation/__main__.py

@@ -45,6 +45,9 @@
     parser.add_argument('--param',
                         nargs='+',
                         help='parameter(s) in filename to use as file labels')
+    parser.add_argument('--input-file-filter', type=str,
+                        help="""Filter which root files in the input data directory to
+                        use using a regular expression""")
     parser.add_argument('--input-files', nargs='+', type=str,
                         help="""Specify the name of the root files directly (either
                         full/relative path or name of files in the input data directory)""")
@@ -94,6 +97,12 @@
         root_files = [ File.from_path(os.path.join(data,f), legendlabel_parameter = arg.param)
                        for f in os.listdir(data) if f.endswith('.root') ]
 
+    if arg.input_file_filter:
+        # Not sure if this can be done in one step so doing it in two
+        filtered_files = [f for f in root_files
+                          if re.search(arg.input_file_filter, f.path) ]
+        root_files = filtered_files
+
     logging.debug(f'ROOT Files: {root_files}')
 
     hd = Differ(label, output_type, *[f for f in root_files if not f.is_events()])