How to get rid of Unnamed 0 column in a pandas DataFrame

Question

I have a situation wherein sometimes when I read a csv from df I get an unwanted index-like column named unnamed 0    file csv     A B C 0 1 2 3 1 4 5 6 2 7 8 9   The CSV is read with this   pd read csv  file csv       Unnamed  0  A  B  C 0           0  1  2  3 1           1  4  5  6 2           2  7  8  9   This is very annoying  Does anyone have an idea on how to get rid of this

User · Answer

To get ride of all Unnamed columns  you can also use regex such as df drop df filter regex  Unname   axis 1  inplace True

User · Answer

You can do the following with Unnamed Columns   Delete unnamed columns Rename them  if you want to use them   file csv  A B C 0 1 2 3 1 4 5 6 2 7 8 9   read file df   pd read csv  file csv    Method 1  Delete Unnamed Columns    delete one by one like column is  Unnamed  0  so use it s name df drop  Unnamed  0   axis 1  inplace True    delete all Unnamed Columns in a single code of line using regex df drop df filter regex  quot Unnamed quot   axis 1  inplace True     Method 2  Rename Unnamed Columns  df rename columns     Unnamed  0   Name    inplace   True  If you want to write out with a blank header as in the input file  just choose  Name  above to be

User · Answer

This is usually caused by your CSV having been saved along with an  unnamed  index  RangeIndex    The fix would actually need to be done when saving the DataFrame  but this isn t always an option   Workaround  read csv with index col  0   argument IMO  the simplest solution would be to read the unnamed column as the index  Specify an index col  0  argument to pd read csv  this reads in the first column as the index   Note the square brackets   df   pd DataFrame  x   index range 5   columns list  abc    df     a  b  c 0  x  x  x 1  x  x  x 2  x  x  x 3  x  x  x 4  x  x  x    Save DataFrame to CSV  df to csv  file csv     lt  - - gt  pd read csv  file csv       Unnamed  0  a  b  c 0           0  x  x  x 1           1  x  x  x 2           2  x  x  x 3           3  x  x  x 4           4  x  x  x    Now try this again  with the extra argument  pd read csv  file csv   index col  0       a  b  c 0  x  x  x 1  x  x  x 2  x  x  x 3  x  x  x 4  x  x  x   Note You could have avoided this in the first place by using index False if the output CSV was created in pandas  if your DataFrame does not have an index to begin with  df to csv  file csv   index False   But as mentioned above  this isn t always an option    Stopgap Solution  Filtering with str match If you cannot modify the code to read write the CSV file  you can just remove the column by filtering with str match  df      Unnamed  0  a  b  c 0           0  x  x  x 1           1  x  x  x 2           2  x  x  x 3           3  x  x  x 4           4  x  x  x  df columns   Index   Unnamed  0    a    b    c    dtype  object    df columns str match  Unnamed     array   True  False  False  False    df loc     df columns str match  Unnamed         a  b  c 0  x  x  x 1  x  x  x 2  x  x  x 3  x  x  x 4  x  x  x

User · Answer

Simply delete that column using  del df  column name

User · Answer

It s the index column  pass pd to csv      index False  to not write out an unnamed index column in the first place  see the to csv   docs  Example  In  37   df   pd DataFrame np random randn 5 3   columns list  abc    pd read csv io StringIO df to csv      Out 37      Unnamed  0         a         b         c 0           0  0 109066 -1 112704 -0 545209 1           1  0 447114  1 525341  0 317252 2           2  0 507495  0 137863  0 886283 3           3  1 452867  1 888363  1 168101 4           4  0 901371 -0 704805  0 088335  compare with  In  38   pd read csv io StringIO df to csv index False     Out 38             a         b         c 0  0 109066 -1 112704 -0 545209 1  0 447114  1 525341  0 317252 2  0 507495  0 137863  0 886283 3  1 452867  1 888363  1 168101 4  0 901371 -0 704805  0 088335  You could also optionally tell read csv that the first column is the index column by passing index col 0  In  40   pd read csv io StringIO df to csv     index col 0   Out 40             a         b         c 0  0 109066 -1 112704 -0 545209 1  0 447114  1 525341  0 317252 2  0 507495  0 137863  0 886283 3  1 452867  1 888363  1 168101 4  0 901371 -0 704805  0 088335

User · Answer

Another case that this might be happening is if your data was improperly written to your csv to have each row end with a comma  This will leave you with an unnamed column Unnamed  x at the end of your data when you try to read it into a df

User · Answer

Simple do this  df   df loc     df columns str contains   Unnamed

[python] How to get rid of "Unnamed: 0" column in a pandas DataFrame?

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