Dataframe not showing in Pycharm
I have faced the same problem with PyCharm 2018.2.2. The reason was having a special character in a column's name as mentioned by Yunzhao . 
If your having a column name like 'R&D' changing it to 'RnD' will fix the problem. It's really strange JetBrains hasn't solved this problem for over 2 years.
I am using PyCharm 2016.2.1 . When I try to view a Pandas dataframe through the newly added feature 'View as DataFrame' in the debugger, this works as expected for a small (e.g. 4x4) DataFrame. 
However when I try to view a DataFrame (generated by custom script) of ~10,000 rows x ~50 columns, I get the message: "Nothing to show". 
When I run the same script (that generates the DataFrame) in Spyder, I am able to view it, so I am pretty sure it's not an error in my script. 
Does anyone know if there is a maximum size to the DataFrames that can be viewed in PyCharm, and if there is a way to change this? 
EDIT:
It seems that the maximum size allowed is 1000 x 15 , as in some cases it gets truncated to this size (when the number of rows is too large, but when there are too many columns pycharm just says 'nothing to show').
Still, I would like to know if there is a way to increase the maximum allowed rows and columns viewable through the DataFrame viewer.