added safety net

1 files changed, 5 insertions, 5 deletions

diff --git a/qolab/file_utils/__init__.py b/qolab/file_utils/__init__.py
index af92c47..49c29ab 100644
--- a/qolab/file_utils/__init__.py
+++ b/qolab/file_utils/__init__.py
@@ -73,15 +73,15 @@ def save_table_with_header(fname, data, header='', comment_symbol='%', skip_head
     # itemFormat examples: 'e', '.15e', 'f'
     fname = filename2os_fname(fname)
     file_exist_flag = os.path.exists(fname)
-    r, c = data.shape
     item_format=str.join('', ['{', f':{item_format}', '}'])
     with open(fname, 'a') as f:
         if not skip_headers_if_file_exist:
             for l in header:
                 f.write(f'{comment_symbol} {l}\n')
-        for r in data:
-            l=item_separator.join( map(item_format.format, r))
-            f.write(l)
-            f.write('\n')
+        if data is not None:
+            for r in data:
+                l=item_separator.join( map(item_format.format, r))
+                f.write(l)
+                f.write('\n')
         f.close()