diff --git a/plots/json2csv.py b/plots/json2csv.py
index 0de1306..25fc9fc 100644
--- a/plots/json2csv.py
+++ b/plots/json2csv.py
@@ -14,6 +14,7 @@
 # val_loss param1 param2 ...
 
 import logging
+import csv
 
 # Set PYTHONPATH=$PWD
 from plottools import *
@@ -32,47 +33,37 @@
 logging.info("Found %i directories." % len(rundirs))
 
 # The CSV file
-fp_out = open(output_file, "w")
-
-# Write CSV header
-fp_out.write("val_loss,")
-header = ",".join(selected)
-fp_out.write(header)
-fp_out.write("\n")
-
-def write_values(fp, val_loss, D, selected):
-    # I think we have to do this for consistent ordering
-    L = [ str(val_loss) ] + [ D[param] for param in selected ]
-    # print(L)
-    fp.write(",".join(L))
-    fp.write("\n")
-
-for rundir in rundirs:
-
-    Js = get_jsons(rundir)
-    if len(Js) == 0:
-        continue
-
-    # Get parameters from the first JSON file
-    record_start = Js[0][0]
-    params = record_start["parameters"]
-    D = {}
-    for entry in params:
-        tokens = entry.split(":")
-        param = tokens[0]
-        if param in selected:
-            value = tokens[1].strip()
-            D[param] = value
-
-    # Get minimum val_loss in the directory
-    val_losses = []
-    for J in Js:
-        record_count  = len(J)
-        record_penult = J[record_count-2]
-        val_losses.append(record_penult["validation_loss"]["set"])
-    val_loss = min(val_losses)
-
-    write_values(fp_out, val_loss, D, selected)
-
-fp_out.close()
+with open(output_file, "w") as fp_out:
+    fieldnames = ["val_loss"] + selected
+    writer = csv.DictWriter(fp_out, fieldnames=fieldnames)
+    writer.writeheader()
+    
+    for rundir in rundirs:
+
+        Js = get_jsons(rundir)
+        if len(Js) == 0:
+            continue
+
+        # Get parameters from the first JSON file
+        record_start = Js[0][0]
+        params = record_start["parameters"]
+        D = {}
+        for entry in params:
+            tokens = entry.split(":")
+            param = tokens[0]
+            if param in selected:
+                # re-join tail e.g. ['data_url', 'ftp', '//ftp.mcs...']
+                value = ":".join(tokens[1:]).strip()
+                D[param] = value
+
+        # Get minimum val_loss in the directory
+        val_losses = []
+        for J in Js:
+            record_penult = J[-2]
+            val_losses.append(record_penult["validation_loss"]["set"])
+        val_loss = min(val_losses)
+        D["val_loss"] = val_loss
+        
+        writer.writerow(D)
+        
 logging.info("Wrote %s ." % output_file)