Python Dataframe sort the dataframe using pd.cut range column

I have a big dataframe and I created a temperature range column by using pd.cut. This is fine. Now I want to know the minimum range in that min-max range column. So, I can use this column to sort the dataframe

My code:

# Goal: sort below dataframe by the 'temp_range' columns
# The column should be sorted as '-60-50','-10-0','0-10','20-30'
xdf = pd.DataFrame(data={'temp_range':['-10-0','20-30','-60-50','0-10']})
xdf['Min. temp range']= xdf['temp_range'].apply(lambda x:x[:3])
xdf

Present solution:

    temp_range  Min. temp range
0   -10-0   -10
1   20-30   20-
2   -60-50  -60
3   0-10    0-1

Expected solution:

    temp_range  Min. temp range
0   -10-0   -10
1   20-30   20
2   -60-50  -60
3   0-10    0

Sort this expected solution by the Min. temp range column

xdf.sort_values('Min. temp range')
    temp_range  Min. temp range
0   -60-50  -60
1   -10-0   -10
2   0-10    0
3   20-30   20

>Solution :

Use str.extract:

xdf['Min. temp range'] = xdf['temp_range'].str.extract('^(-?\d+)')

Output:

  temp_range Min. temp range
0      -10-0             -10
1      20-30              20
2     -60-50             -60
3       0-10               0

regex demo

If you don’t need the column and just want to sort:

xdf.sort_values(by='temp_range', key=lambda s: pd.to_numeric(s.str.extract('^(-?\d+)', expand=False)))

Output:

  temp_range
2     -60-50
0      -10-0
3       0-10
1      20-30