我有一个类别和金额的数据框。可以使用冒号分隔的字符串将类别嵌套到无限级别的子类别中。我希望按降序排序。但以所示的分层类型方式。
我如何对其进行排序
CATEGORY AMOUNT
Transport 5000
Transport : Car 4900
Transport : Train 100
Household 1100
Household : Utilities 600
Household : Utilities : Water 400
Household : Utilities : Electric 200
Household : Cleaning 100
Household : Cleaning : Bathroom 75
Household : Cleaning : Kitchen 25
Household : Rent 400
Living 250
Living : Other 150
Living : Food 100
编辑： 数据框：
pd.DataFrame({
"category": ["Transport", "Transport : Car", "Transport : Train", "Household", "Household : Utilities", "Household : Utilities : Water", "Household : Utilities : Electric", "Household : Cleaning", "Household : Cleaning : Bathroom", "Household : Cleaning : Kitchen", "Household : Rent", "Living", "Living : Other", "Living : Food"],
"amount": [5000, 4900, 100, 1100, 600, 400, 200, 100, 75, 25, 400, 250, 150, 100]
})
注意：这是我想要的顺序。排序之前可以是任意顺序。
答案 0 :(得分：4)
一种方法可能是首先str.split类别列。
df_ = df['category'].str.split(' : ', expand=True)
print (df_.head())
0 1 2
0 Transport None None
1 Transport Car None
2 Transport Train None
3 Household None None
4 Household Utilities None
然后获取列的数量，而您想要的是基于以下条件获得每组的最大数量：
您可以使用groupby.transform和max来完成此操作，并合并创建的每个列。
s = df['amount']
l_cols = list(df_.columns)
dfa = pd.concat([s.groupby([df_[col] for col in range(0, lv+1)]).transform('max')
for lv in l_cols], keys=l_cols, axis=1)
print (dfa)
0 1 2
0 5000 NaN NaN
1 5000 4900.0 NaN
2 5000 100.0 NaN
3 1100 NaN NaN
4 1100 600.0 NaN
5 1100 600.0 400.0
6 1100 600.0 200.0
7 1100 100.0 NaN
8 1100 100.0 75.0
9 1100 100.0 25.0
10 1100 400.0 NaN
11 250 NaN NaN
12 250 150.0 NaN
13 250 100.0 NaN
现在，您只需要按正确的顺序依次在所有列上依次sort_values，首先是0，然后是1，然后是2 ...，获取索引并使用loc以预期的方式对df进行排序
dfa = dfa.sort_values(l_cols, na_position='first', ascending=False)
dfs = df.loc[dfa.index] #here you can reassign to df directly
print (dfs)
category amount
0 Transport 5000
1 Transport : Car 4900
2 Transport : Train 100
3 Household 1100
4 Household : Utilities 600
5 Household : Utilities : Water 400
6 Household : Utilities : Electric 200
10 Household : Rent 400 #here is the one difference with this data
7 Household : Cleaning 100
8 Household : Cleaning : Bathroom 75
9 Household : Cleaning : Kitchen 25
11 Living 250
12 Living : Other 150
13 Living : Food 100
答案 1 :(得分：1)
我打包了@Ben。 T的答案进入了一个更通用的函数，希望阅读起来更清楚！
编辑：我对函数进行了更改，以按列进行分组，而不是一一列出以解决@Ben指出的潜在问题。注释中的T。
import pandas as pd
def category_sort_df(df, sep, category_col, numeric_col, ascending=False):
'''Sorts dataframe by nested categories using `sep` as the delimiter for `category_col`.
Sorts numeric columns in descending order by default.
Returns a copy.'''
df = df.copy()
try:
to_sort = pd.to_numeric(df[numeric_col])
except ValueError:
print(f'Column `{numeric_col}` is not numeric!')
raise
categories = df[category_col].str.split(sep, expand=True)
# Strips any white space before and after sep
categories = categories.apply(lambda x: x.str.split().str[0], axis=1)
levels = list(categories.columns)
to_concat = []
for level in levels:
# Group by columns in order rather than one at a time
level_by = [df_[col] for col in range(0, level+1)]
gb = to_sort.groupby(level_by)
to_concat.append(gb.transform('max'))
dfa = pd.concat(to_concat, keys=levels, axis=1)
ixs = dfa.sort_values(levels, na_position='first', ascending=False).index
df = df.loc[ixs].copy()
return df
使用Python 3.7.3，熊猫0.24.2
答案 2 :(得分：0)
要回答我自己的问题：我找到了一种方法。有点long，但是在这里。
import numpy as np
import pandas as pd
def sort_tree_df(df, tree_column, sort_column):
sort_key = sort_column + '_abs'
df[sort_key] = df[sort_column].abs()
df.index = pd.MultiIndex.from_frame(
df[tree_column].str.split(":").apply(lambda x: [y.strip() for y in x]).apply(pd.Series))
sort_columns = [df[tree_column].values, df[sort_key].values] + [
df.groupby(level=list(range(0, x)))[sort_key].transform('max').values
for x in range(df.index.nlevels - 1, 0, -1)
]
sort_indexes = np.lexsort(sort_columns)
df_sorted = df.iloc[sort_indexes[::-1]]
df_sorted.reset_index(drop=True, inplace=True)
df_sorted.drop(sort_key, axis=1, inplace=True)
return df_sorted
sort_tree_df(df, 'category', 'amount')
答案 3 :(得分：0)
如果您不介意添加额外的列，则可以从类别中提取主要类别，然后按金额/主要类别/类别进行排序，即：
df['main_category'] = df.category.str.extract(r'^([^ ]+)')
df.sort_values(['main_category', 'amount', 'category'], ascending=False)[['category', 'amount']]
输出：
category amount
0 Transport 5000
1 Transport : Car 4900
2 Transport : Train 100
11 Living 250
12 Living : Other 150
13 Living : Food 100
3 Household 1100
4 Household : Utilities 600
5 Household : Utilities : Water 400
10 Household : Rent 400
6 Household : Utilities : Electric 200
7 Household : Cleaning 100
8 Household : Cleaning : Bathroom 75
9 Household : Cleaning : Kitchen 25
请注意，仅当您的主要类别是不带空格的单个单词时，此方法才有效。否则，您将需要以其他方式进行操作，即。提取所有非冒号并删除尾随空格：
df['main_category'] = df.category.str.extract(r'^([^:]+)')
df['main_category'] = df.main_category.str.rstrip()