pandas dataframe to_csv works with sep='\n' but not sep='\t'

Question

I try to print my large dataframe to csv file but the tab separation sep='\t' does not work. I then test with newline sep='\n', it seems work ok, break all the elements by newline. What are possibly wrong here?

The code is so simple like

df_M.to_csv('report'+filename, header=True, sep='\t', index=False)

The example of data (the protein column is very long), I mark where to separate by |

"protein |  cl      | pept |    [M] |  [M+1H+]1+ |  [M+2H+]2+"      
"ALBU_HUMAN_UPS Serum albumin (Chain 26-609) - Homo sapiens (Human)|    0|   AWAVAR|        672.37072|            673.378| out-of-range"        
"ALBU_HUMAN_UPS Serum albumin (Chain 26-609) - Homo sapiens (Human)|    0|  TPVSDR| 673.3394900000002|  674.3467700000002|  out-of-range"       
"ALBU_HUMAN_UPS Serum albumin (Chain 26-609) - Homo sapiens (Human)|    0|  NYAEAK| 694.3285900000001|  695.3358700000001|  out-of-range"       
"

Answer 1

Are you saving the data as .tsv format? your data is tsv file as you are separating the data with '\t' which is tab. csv file must be separated by ",".

If you wanna save data with .csv format you need to separate by ","

Link for .csv RFC. http://www.ietf.org/rfc/rfc4180.txt