output confusion in sort_values of Pandas

[ift38375]

Given below is small program in python:
import pandas as pd
ontutD = {'Tutor': ['Tahira','Gagan','Anusha','Jacob','venkat',
'Tahira','Gagan','Anusha','Jacob','venkat',
'Tahira','Gagan','Anusha','Jacob','venkat',
'Tahira','Gagan','Anusha','Jacob','venkat'],
'Classes' : [28,36,41,32,40,36,40,36,40,46,24,30,44,40,32,36,32,36,42,38],
'Quarter' : [1,1,1,1,1,2,2,2,2,2,3,3,3,3,3,4,4,4,4,4],
'Country' : [ 'USA','UK','Japan','USA','Brazil','USA','USA','Japan',
'Brazil','USA','Brazil','USA','UK','Brazil','USA','Japan',
'Japan','Brazil','UK','USA']
}
df1 = pd.DataFrame(ontutD)
ks = df1.sort_values('Country')
print (ks)

Python 3.7.3 Output :

Output:
    Tutor  Classes  Quarter Country
17  Anusha       36        4  Brazil
4   venkat       40        1  Brazil
8    Jacob       40        2  Brazil
10  Tahira       24        3  Brazil
13   Jacob       40        3  Brazil
2   Anusha       41        1   Japan
16   Gagan       32        4   Japan
15  Tahira       36        4   Japan
7   Anusha       36        2   Japan
1    Gagan       36        1      UK
18   Jacob       42        4      UK
12  Anusha       44        3      UK
0   Tahira       28        1     USA
14  venkat       32        3     USA
9   venkat       46        2     USA
6    Gagan       40        2     USA
5   Tahira       36        2     USA
3    Jacob       32        1     USA
11   Gagan       30        3     USA
19  venkat       38        4     USA

My confusion in index number:17, it will be come at 5th position ? please correct me

Output:
    Tutor  Classes  Quarter Country
4   venkat       40        1  Brazil
8    Jacob       40        2  Brazil
10  Tahira       24        3  Brazil
13   Jacob       40        3  Brazil
17  Anusha       36        4  Brazil
2   Anusha       41        1   Japan
16   Gagan       32        4   Japan
15  Tahira       36        4   Japan
7   Anusha       36        2   Japan
1    Gagan       36        1      UK
18   Jacob       42        4      UK
12  Anusha       44        3      UK
0   Tahira       28        1     USA
14  venkat       32        3     USA
9   venkat       46        2     USA
6    Gagan       40        2     USA
5   Tahira       36        2     USA
3    Jacob       32        1     USA
11   Gagan       30        3     USA
19  venkat       38        4     USA

[ThomasL]

you need to specify type of sorting algorithm to be mergesort

ks = df1.sort_values('Country', kind='mergesort')

default is 'quicksort' which is not stable