Improvements to create-train-val-split.

+ Use python2 for consistency with our other Python code.
+ The previous version left empty subdirectories.
  This modification deletes them.

util/create-train-val-split.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python2
 #
 # Copyright 2015 Carnegie Mellon University
 #
@@ -15,37 +15,44 @@
 # limitations under the License.
 
 import argparse
+import errno
 import os
 import random
 import shutil
 
+def mkdirP(path):
+    try:
+        os.makedirs(path)
+    except OSError as exc:  # Python >2.5
+        if exc.errno == errno.EEXIST and os.path.isdir(path):
+            pass
+        else:
+            raise
 
 def getImgs(imageDir):
     exts = ["jpg", "png"]
 
     # All images with one image from each class put into the validation set.
     allImgsM = []
-    classes = {}  # Directory Names -> 0-based indexes for Caffe classes.
+    classes = set()
     valImgs = []
     for subdir, dirs, files in os.walk(imageDir):
         for fName in files:
             (imageClass, imageName) = (os.path.basename(subdir), fName)
             if any(imageName.lower().endswith("." + ext) for ext in exts):
                 if imageClass not in classes:
-                    caffeClass = len(classes)  # 0-based indexes.
-                    classes[imageClass] = caffeClass
+                    classes.add(imageClass)
                     valImgs.append((imageClass, imageName))
                 else:
                     allImgsM.append((imageClass, imageName))
-    return (allImgsM, classes, valImgs)
+    print("+ Number of Classes: '{}'.".format(len(classes)))
+    return (allImgsM, valImgs)
 
 
 def createTrainValSplit(imageDir, valRatio):
     print("+ Val ratio: '{}'.".format(valRatio))
 
-    (allImgsM, classes, valImgs) = getImgs(imageDir)
-
-    print("+ Number of Classes: '{}'.".format(len(classes)))
+    (allImgsM, valImgs) = getImgs(imageDir)
 
     trainValIdx = int((len(allImgsM) + len(valImgs)) * valRatio) - len(valImgs)
     assert(trainValIdx > 0)  # Otherwise, valRatio is too small.
@@ -61,16 +68,21 @@ def createTrainValSplit(imageDir, valRatio):
         origPath = os.path.join(imageDir, person, img)
         newDir = os.path.join(imageDir, 'train', person)
         newPath = os.path.join(imageDir, 'train', person, img)
-        os.makedirs(newDir, exist_ok=True)
+        mkdirP(newDir)
         shutil.move(origPath, newPath)
 
     for person, img in valImgs:
         origPath = os.path.join(imageDir, person, img)
         newDir = os.path.join(imageDir, 'val', person)
         newPath = os.path.join(imageDir, 'val', person, img)
-        os.makedirs(newDir, exist_ok=True)
+        mkdirP(newDir)
         shutil.move(origPath, newPath)
 
+    for person, img in valImgs:
+        d = os.path.join(imageDir, person)
+        if os.path.isdir(d):
+            os.rmdir(d)
+
 if __name__ == '__main__':
     parser = argparse.ArgumentParser()
     parser.add_argument(