查找列中重复的单词并使用 pandas 根据出现次数对其进行排序

Question

        A                             B
 1) Italy                   Transport for London.....
 2) Italy                   Roseanne Barr Actor leavin..... 
 3) America                 Americas Transport for London........ 
 4) America                 Transport for London.....
 5) America                 Roseanne Barr Actor leavin..... 
 6) France                  Americas Transport for London........ 

这是我的 Excel 表的一个示例，我希望它根据 A 列中出现的次数进行排序。就像美国在列中出现 3 次，然后美国的行应该转移到顶部，意大利的行跟随美国和那么法国的行应该在最后，因为它在 A 列中的出现率最低。

Answer 1

使用transform 和argsort in descending order 作为职位并通过iloc 选择：

df = df.iloc[(-df.groupby('A')['A'].transform('size')).argsort()]
print (df)
          A                              B
3)  America  Americas Transport for London
4)  America           Transport for London
5)  America     Roseanne Barr Actor leavin
1)    Italy           Transport for London
2)    Italy     Roseanne Barr Actor leavin
6)   France  Americas Transport for London

或创建新列并排序：

df['new'] = df.groupby('A')['A'].transform('size')

df = df.sort_values('new', ascending=False)
print (df)
          A                              B  new
3)  America  Americas Transport for London    3
4)  America           Transport for London    3
5)  America     Roseanne Barr Actor leavin    3
1)    Italy           Transport for London    2
2)    Italy     Roseanne Barr Actor leavin    2
6)   France  Americas Transport for London    1

Answer 2

使用collections.Counter 创建计数字典：

from collections import Counter

df = pd.DataFrame([['Italy', 'Transport for London'],
                   ['Italy', 'Roseanne Barr Actor leavin'],
                   ['America', 'Americas Transport for London'],
                   ['America', 'Transport for London'],
                   ['America', 'Roseanne Barr Actor leavin'],
                   ['France', 'Americas Transport for London']],
                  columns=['A', 'B'])

# calculate counts
c = Counter(df['A'])

# apply reordering
df = df.iloc[df['A'].map(c).argsort()[::-1]]

# save to excel
df.to_excel('file.xlsx', index=False)

结果：

print(df)

         A                              B
4  America     Roseanne Barr Actor leavin
3  America           Transport for London
2  America  Americas Transport for London
1    Italy     Roseanne Barr Actor leavin
0    Italy           Transport for London
5   France  Americas Transport for London