implement average calling hadd and scale

mctools/common/average.py

@@ -1,26 +1,55 @@
 #!/usr/bin/env python3
+#
+# https://github.com/kbat/mc-tools
+#
 
-from sys import argv, exit
-from string import ascii_lowercase, digits
-from os  import system
-from random import choice
+import argparse, tempfile
+import logging
+import math
+from sys import exit
+import os
+import ROOT
+ROOT.PyConfig.IgnoreCommandLineOptions = True
 
 def main():
+    """ Merge and average ROOT files
     """
-    hadd + average
-    """
 
-    outfile = argv[1]
-    tmpfname = '/tmp/hadd-av' + ''.join(choice(ascii_lowercase + digits) for x in range(8)) + '.root'
-    print(tmpfname)
+    parser = argparse.ArgumentParser(description=main.__doc__,
+                                     formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+                                     epilog="Homepage: https://github.com/kbat/mc-tools")
+
+    parser.add_argument('-f', '--force', action='store_true', default=False, dest='overwrite',
+                        help='overwrite the target output ROOT file')
+    parser.add_argument('-o', dest='target', type=str, help='target file')
+    parser.add_argument('sources', type=str, help='source files', nargs='+')
+    parser.add_argument('-v', '--verbose', action='store_true', default=False, dest='verbose', help='explain what is being done   ')
+
+    args = parser.parse_args()
+
+    if not args.overwrite and os.path.exists(args.target):
+        logging.critical("File %s exists. Use -f to overwrite" % args.target)
+        exit(1)
+
+    sources = args.sources
+
+    for f in sources:
+        if not os.path.exists(f):
+            print(f"WARNING: {f} does not exits - skipping")
+            sources.remove(f)
 
- #   open(tmpfile).close()
-    files = argv[2:]
-    nfiles = len(files)
+    if args.verbose:
+        print(sources)
 
-    if system("hadd %s %s" % (tmpfname, ' '.join(files))): exit(1)
+    n = len(sources)
 
-    print('number of files:', nfiles)
+    with tempfile.TemporaryDirectory() as tmp:
+        unscaled = os.path.join(tmp, "unscaled.root")
+        print(unscaled)
+        cmd = "hadd %s %s" % (unscaled, " ".join(sources))
+        os.system(cmd)
+        cmd = f"scale -n {n} {unscaled} -o {args.target}"
+        os.system(cmd)
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     exit(main())