如何按值对df行排序？

Question

df looks like below: Age, Sex... they are all index,with only one column named Importance

                        Importance
Onset Delta               0.121048
Site of Onset - Limb      0.000036
Site of Onset - Bulbar    0.000382
Age                       0.008650
Sex                       0.000978
Race - Caucasian          0.001274
Race - Other              0.001776
Sodium_Dmax               0.007689

I would like to re-shape the df, by ranking rows according to Importance ,how could I do that? I tried

groupby(['Importance'],as_index=False)

But not work Thanks

Answer 1

Use the sort_values function:

test = df.sort_values('Importance')

assuming df is the dataframe

Answer 2

If your data's structure is dataframe, you can use sort function:

df.sort(['Importance'],ascending=True) or 
df.sort(['Importance'],ascending=False)

The "True" or "False" depends on your option, it means your data are listed in descending order or ascending order.

Answer 3

df.groupby() would be used if you wanted aggregations on the data, what you're looking for is df.sort_values() .

With df.sort_values() , you pass in the by string telling pandas which column to sort on.

For your code, I would expect df.sort_values(by='Importance')

You can assign the result of this to a new data frame, or pass in the inplace=true parameter to sort the df.

You can view the documentation for the df.sort_values() method here