pythonpandas

Pandas - rearrange columns if column exists

I have a dataframes that are in jumbled order how can I rearrange the columns if they exits.

One      Two       Three  Six    Four     Five
1         2         3      6      4         5
1         2         3      6      4         5
...

How can I arrange this columns in order? The issue here is that all six column might not be there in all occasions. So I need a simple line that can arrange it in order of One Two Three Four Five Six if that column exits. I mean if Two is not in df then it should be One Three Four Five Six

Solution

  • You can change order by DataFrame.reindex and then remove only missing values columns:

    df1 = (df.reindex(['One', 'Two','Three','Four','Five','Six'], axis=1)
          .dropna(how='all', axis=1))
print (df1)
   One  Three  Four  Five  Six
0    1      3     4     5    6
1    1      3     4     5    6

    Or is possible create order categoricals in columns and then sorting columns:

    c = ['One', 'Two','Three','Four','Five','Six']
df.columns = pd.CategoricalIndex(df.columns, categories=c, ordered=True)
df1 = df.sort_index(axis=1)
print (df1)
   One  Three  Four  Five  Six
0    1      3     4     5    6
1    1      3     4     5    6