From 48e280fcb3f2789f520ba0ce87cdbd7b5731ba60 2014-04-10 05:07:33
From: MinRK <benjaminrk@gmail.com>
Date: 2014-04-10 05:07:33
Subject: [PATCH] only process cr if it's found

because re.sub is crazy slow.
---

diff --git a/IPython/nbconvert/preprocessors/coalescestreams.py b/IPython/nbconvert/preprocessors/coalescestreams.py
index 5226303..12dbc51 100644
--- a/IPython/nbconvert/preprocessors/coalescestreams.py
+++ b/IPython/nbconvert/preprocessors/coalescestreams.py
@@ -70,7 +70,7 @@ def coalesce_streams(cell, resources, index):
     
     # process \r characters
     for output in new_outputs:
-        if output.output_type == 'stream':
+        if output.output_type == 'stream' and '\r' in output.text:
             output.text = cr_pat.sub('', output.text)
 
     cell.outputs = new_outputs