Extracting specific selected columns to new DataFrame as a copy

Question

I have a pandas DataFrame with 4 columns and I want to create a new DataFrame that only has three of the columns   This question is similar to  Extracting specific columns from a data frame but for pandas not R   The following code does not work  raises an error  and is certainly not the pandasnic way to do it    import pandas as pd old   pd DataFrame   A     4 5    B     10 20    C     100 50    D     -30 -50    new   pd DataFrame zip old A  old C  old D     raises TypeError  data argument can t be an iterator    What is the pandasnic way to do it

User · Answer

As far as I can tell  you don t necessarily need to specify the axis when using the filter function   new   old filter   A   B   D      returns the same dataframe as  new   old filter   A   B   D    axis 1

User · Answer

There is a way of doing this and it actually looks similar to R  new   old   A    C    D    copy     Here you are just selecting the columns you want from the original data frame and creating a variable for those  If you want to modify the new dataframe at all you ll probably want to use  copy   to avoid a SettingWithCopyWarning   An alternative method is to use filter which will create a copy by default   new   old filter   A   B   D    axis 1    Finally  depending on the number of columns in your original dataframe  it might be more succinct to express this using a drop  this will also create a copy by default    new   old drop  B   axis 1

User · Answer

Generic functional form  def select columns data frame  column names       new frame   data frame loc    column names      return new frame   Specific for your problem above  selected columns     A    C    D   new   select columns old  selected columns

User · Answer

Another simpler way seems to be    new   pd DataFrame  old A  old B  old C   transpose     where old column name will give you a series   Make a list of all the column-series you want to retain and pass it to the DataFrame constructor  We need to do a transpose to adjust the shape    In  14  pd DataFrame  old A  old B  old C   transpose   Out 14       A   B    C 0  4  10  100 1  5  20   50

User · Answer

The easiest way is  new   old   A   C   D

User · Answer

columns by index     selected column index  1  6  7 new   old iloc      1  6  7   copy

User · Answer

If you want to have a new data frame then   import pandas as pd old   pd DataFrame   A     4 5    B     10 20    C     100 50    D     -30 -50    new   old   A    C    D

[python] Extracting specific selected columns to new DataFrame as a copy

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