CODEWITHSUNDEEP
pythonpandas
Nivi
Nivi

Reputation: 1137

Extract column names and sort them in Pandas

I have a pandas dataframe that looks like the one below:

A  |  B  | C   | D   |  E  |
1  |  2  | 3.5 | 2.3 | 4.0 |

I want to always extract any columns C through E that are greater than 2.5 and sort them in descending order of their values.

For the above example:

E,C is the output

Upvotes: 1

Views: 469

Answers (2)

jpp
jpp

Reputation: 164773

One way is to extract values for your required columns via pd.DataFrame.columns.get_loc. Then filter and use the pd.Series.index:

vals = df.iloc[0, df.columns.get_loc('C'):]  # or df.loc[0, 'C':]
res = vals[vals > 2.5].sort_values(ascending=False).index

print(res)

Index(['E', 'C'], dtype='object')

Upvotes: 1

cs95
cs95

Reputation: 402814

transpose + sort_values

v = df.T.squeeze().loc['C':'E'].sort_values(ascending=False)
v.index[v.gt(2.5)].tolist()
['E', 'C']

stack + sort_values

v = (
   df.stack()
     .reset_index(level=0, drop=True)
     .loc['C':'E']
     .sort_values(ascending=False)
)
v.index[v.gt(2.5)].tolist()
['E', 'C']

Upvotes: 2

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