我在pandas dataframe中有这个测试表
Leaf_category_id session_id product_id
0 111 1 987
3 111 4 987
4 111 1 741
1 222 2 654
2 333 3 321
这是我之前提出的问题的延伸，@ jazrael回答了这个问题。 view answer
所以在获取product_id列中的值之后（只是一个假设，与我上一个问题的输出略有不同，
|product_id |
---------------------------
|111,987,741,34,12 |
|987,1232 |
|654,12,324,465,342,324 |
|321,741,987 |
|324,654,862,467,243,754 |
|6453,123,987,741,34,12 |
等等， 我想创建一个新列，其中一行中的所有值都应该作为一个bigram与下一个，最后一个。在行中与第一行结合，例如：
|product_id |Bigram
-------------------------------------------------------------------------
|111,987,741,34,12 |(111,987),**(987,741)**,(741,34),(34,12),(12,111)
|987,1232 |(987,1232),(1232,987)
|654,12,324,465,342,32 |(654,12),(12,324),(324,465),(465,342),(342,32),(32,654)
|321,741,987 |(321,741),**(741,987)**,(987,321)
|324,654,862 |(324,654),(654,862),(862,324)
|123,987,741,34,12 |(123,987),(987,741),(34,12),(12,123)
忽略**（我稍后会告诉你为什么我主演了这个）
获得二元组的代码是
for i in df.Leaf_category_id.unique():
print (df[df.Leaf_category_id == i].groupby('session_id')['product_id'].apply(lambda x: list(zip(x, x[1:]))).reset_index())
从这个df开始，我想考虑一下bigram列并再创建一个名为frequency的列，它给出了bigram的频率。
注*：（987,741）和（741,987）应被视为相同，并且应删除一个公共条目，因此（987,741）的频率应为2。 类似的是（34,12）它发生两次，所以频率应该是2
|Bigram
---------------
|(111,987),
|**(987,741)**
|(741,34)
|(34,12)
|(12,111)
|**(741,987)**
|(987,321)
|(34,12)
|(12,123)
最终结果应该是。
|Bigram | frequency |
--------------------------
|(111,987) | 1
|(987,741) | 2
|(741,34) | 1
|(34,12) | 2
|(12,111) | 1
|(987,321) | 1
|(12,123) | 1
我希望在这里找到答案，请帮助我，我已尽可能详细说明。
答案 0 :(得分：2)
试试这段代码
from itertools import combinations
import pandas as pd
df = pd.DataFrame.from_csv("data.csv")
#consecutive
grouped_consecutive_product_ids = df.groupby(['Leaf_category_id','session_id'])['product_id'].apply(lambda x: [tuple(sorted(pair)) for pair in zip(x,x[1:])]).reset_index()
df1=pd.DataFrame(grouped_consecutive_product_ids)
s=df1.product_id.apply(lambda x: pd.Series(x)).unstack()
df2=pd.DataFrame(s.reset_index(level=0,drop=True)).dropna()
df2.rename(columns = {0:'Bigram'}, inplace = True)
df2["freq"] = df2.groupby('Bigram')['Bigram'].transform('count')
bigram_frequency_consecutive = df2.drop_duplicates(keep="first").sort_values("Bigram").reset_index()
del bigram_frequency_consecutive["index"]
组合（所有可能的二元组）
from itertools import combinations
import pandas as pd
df = pd.DataFrame.from_csv("data.csv")
#combinations
grouped_combination_product_ids = df.groupby(['Leaf_category_id','session_id'])['product_id'].apply(lambda x: [tuple(sorted(pair)) for pair in combinations(x,2)]).reset_index()
df1=pd.DataFrame(grouped_combination_product_ids)
s=df1.product_id.apply(lambda x: pd.Series(x)).unstack()
df2=pd.DataFrame(s.reset_index(level=0,drop=True)).dropna()
df2.rename(columns = {0:'Bigram'}, inplace = True)
df2["freq"] = df2.groupby('Bigram')['Bigram'].transform('count')
bigram_frequency_combinations = df2.drop_duplicates(keep="first").sort_values("Bigram").reset_index()
del bigram_frequency_combinations["index"]
data.csv包含
Leaf_category_id,session_id,product_id
0,111,1,111
3,111,4,987
4,111,1,741
1,222,2,654
2,333,3,321
5,111,1,87
6,111,1,34
7,111,1,12
8,111,1,987
9,111,4,1232
10,222,2,12
11,222,2,324
12,222,2,465
13,222,2,342
14,222,2,32
15,333,3,321
16,333,3,741
17,333,3,987
18,333,3,324
19,333,3,654
20,333,3,862
21,222,1,123
22,222,1,987
23,222,1,741
24,222,1,34
25,222,1,12
结果bigram_frequency_consecutive将是
Bigram freq
0 (12, 34) 2
1 (12, 324) 1
2 (12, 654) 1
3 (12, 987) 1
4 (32, 342) 1
5 (34, 87) 1
6 (34, 741) 1
7 (87, 741) 1
8 (111, 741) 1
9 (123, 987) 1
10 (321, 321) 1
11 (321, 741) 1
12 (324, 465) 1
13 (324, 654) 1
14 (324, 987) 1
15 (342, 465) 1
16 (654, 862) 1
17 (741, 987) 2
18 (987, 1232) 1
结果bigram_frequency_combinations将是
Bigram freq
0 (12, 32) 1
1 (12, 34) 2
2 (12, 87) 1
3 (12, 111) 1
4 (12, 123) 1
5 (12, 324) 1
6 (12, 342) 1
7 (12, 465) 1
8 (12, 654) 1
9 (12, 741) 2
10 (12, 987) 2
11 (32, 324) 1
12 (32, 342) 1
13 (32, 465) 1
14 (32, 654) 1
15 (34, 87) 1
16 (34, 111) 1
17 (34, 123) 1
18 (34, 741) 2
19 (34, 987) 2
20 (87, 111) 1
21 (87, 741) 1
22 (87, 987) 1
23 (111, 741) 1
24 (111, 987) 1
25 (123, 741) 1
26 (123, 987) 1
27 (321, 321) 1
28 (321, 324) 2
29 (321, 654) 2
30 (321, 741) 2
31 (321, 862) 2
32 (321, 987) 2
33 (324, 342) 1
34 (324, 465) 1
35 (324, 654) 2
36 (324, 741) 1
37 (324, 862) 1
38 (324, 987) 1
39 (342, 465) 1
40 (342, 654) 1
41 (465, 654) 1
42 (654, 741) 1
43 (654, 862) 1
44 (654, 987) 1
45 (741, 862) 1
46 (741, 987) 3
47 (862, 987) 1
48 (987, 1232) 1
在上述情况下，它由两者分组
答案 1 :(得分：1)
我们将从product_id中提取值，创建已排序并进行重复数据删除的bigrams，并计算它们以获取频率，然后填充数据框。
from collections import Counter
# assuming your data frame is called 'df'
bigrams = [list(zip(x,x[1:])) for x in df.product_id.values.tolist()]
bigram_set = [tuple(sorted(xx) for x in bigrams for xx in x]
freq_dict = Counter(bigram_set)
df_freq = pd.DataFrame([list(f) for f in freq_dict], columns=['bigram','freq'])