Cannot get the correct corresponding results in python

Question

I'm trying to create a ranking for string answers and create frequency distribution with the ranking (and use it for data visualization as well).

I tried to use this code:

education_rank = {
    ' 1st-4th': 2, ' Preschool': 1, ' 5th-6th': 3,  ' 7th-8th': 4,
    ' 9th': 5, ' 10th':6, ' 11th': 7,  ' 12th': 8, ' HS-grad': 9,
    ' Assoc-voc': 10,  ' Assoc-acdm': 11, ' Some-college': 12,
    ' Bachelors': 13, ' Prof-school': 14, ' Masters': 15, ' Doctorate': 16}

adult_data.education.rank = education_rank.keys()
fd_education = pd.value_counts(adult_data.education)
print(fd_education)
fd_education.index = education_rank.values()
print(fd_education)

Results:

The former one is the correct frequency distribution. However, when I add the ranking, the frequency distribution results in the second column remain the same and would not change accordingly.

 HS-grad         15784
 Some-college    10878
 Bachelors        8025
 Masters          2657
 Assoc-voc        2061
 11th             1812
 Assoc-acdm       1601
 10th             1389
 7th-8th           955
 Prof-school       834
 9th               756
 12th              657
 Doctorate         594
 5th-6th           509
 1st-4th           247
 Preschool          83
Name: education, dtype: int64
2     15784
1     10878
3      8025
4      2657
5      2061
6      1812
7      1601
8      1389
9       955
10      834
11      756
12      657
13      594
14      509
15      247
16       83
Name: education, dtype: int64

Answer 1

等待大神答复